This is a tree we use, convert back to a mtt using the mts maker. You'll probably have to make some adjustments for your data but it should be a good starting point.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE TTMAKER SYSTEM "ttmaker60.dtd">
<?ANALYZE?><TTMAKER Version="6.0"><NEWTREE Filename="C:\Mercator6.7\Standard Resource Library\Hubware\Trees\WMQ_HDR_RFH2.mtt"><ROOT SimpleTypeName="ROOT" SetUpProperties="DEFAULT" SetUpComponents="DELETE" OrderSubtypes="ASCENDING"><Sequence partition="NO"><Implicit/></Sequence>
<CharTextWestern><Size Min="0" Max="S"/>
<Western CharSet="NATIVE"/>
<ValueRestrictions IgnoreCase="NO" Rule="INCLUDE"></ValueRestrictions>
</CharTextWestern>
</ROOT>
<ITEM SimpleTypeName="Field" CategoryOrItemParent="ROOT" partition="NO" OrderSubtypes="ASCENDING"><CharTextWestern><Size Min="0" Max="S"/>
<Western CharSet="NATIVE"/>
<ValueRestrictions IgnoreCase="NO" Rule="INCLUDE"></ValueRestrictions>
</CharTextWestern>
</ITEM>
<ITEM SimpleTypeName="CodedCharSetID" CategoryOrItemParent="Field ROOT" partition="NO" OrderSubtypes="ASCENDING"><BinaryNumber><BinInt Length="4" Sign="NO" ByteOrder="BIGENDIAN"/>
<ValueRestrictions IgnoreCase="NO" Rule="INCLUDE"></ValueRestrictions>
</BinaryNumber>
</ITEM>
<ITEM SimpleTypeName="Data" CategoryOrItemParent="Field ROOT" partition="NO" OrderSubtypes="ASCENDING"><CharTextWestern><Size Min="0" Max="S"/>
<Western CharSet="NATIVE"/>
<ValueRestrictions IgnoreCase="NO" Rule="INCLUDE"></ValueRestrictions>
</CharTextWestern>
</ITEM>
<ITEM SimpleTypeName="Encoding" CategoryOrItemParent="Field ROOT" partition="NO" OrderSubtypes="ASCENDING"><BinaryNumber><BinInt Length="4" Sign="NO" ByteOrder="BIGENDIAN"/>
<ValueRestrictions IgnoreCase="NO" Rule="INCLUDE"></ValueRestrictions>
</BinaryNumber>
</ITEM>
<ITEM SimpleTypeName="Flags" CategoryOrItemParent="Field ROOT" partition="NO" OrderSubtypes="ASCENDING"><BinaryNumber><BinInt Length="4" Sign="NO" ByteOrder="BIGENDIAN"/>
<ValueRestrictions IgnoreCase="NO" Rule="INCLUDE"></ValueRestrictions>
</BinaryNumber>
</ITEM>
<ITEM SimpleTypeName="Format" CategoryOrItemParent="Field ROOT" partition="NO" OrderSubtypes="ASCENDING"><CharTextWestern><Size Min="8" Max="8"/>
<PadText Justify="LEFT" ApplyPad="ANYCONTEXT"><PadValue><SP></PadValue>
<PaddedToMinContent/>
</PadText>
<Western CharSet="NATIVE"/>
<ValueRestrictions IgnoreCase="NO" Rule="INCLUDE"></ValueRestrictions>
</CharTextWestern>
</ITEM>
<ITEM SimpleTypeName="NameValueCCSID" CategoryOrItemParent="Field ROOT" partition="NO" OrderSubtypes="ASCENDING"><BinaryNumber><BinInt Length="4" Sign="NO" ByteOrder="BIGENDIAN"/>
<ValueRestrictions IgnoreCase="NO" Rule="INCLUDE"></ValueRestrictions>
</BinaryNumber>
</ITEM>
<ITEM SimpleTypeName="NameValueData" CategoryOrItemParent="Field ROOT" partition="NO" OrderSubtypes="ASCENDING"><CharTextWestern><Size Min="0" Max="S"/>
<Western CharSet="NATIVE"/>
<ValueRestrictions IgnoreCase="NO" Rule="INCLUDE"></ValueRestrictions>
</CharTextWestern>
</ITEM>
<ITEM SimpleTypeName="NameValueLength" CategoryOrItemParent="Field ROOT" partition="NO" OrderSubtypes="ASCENDING"><BinaryNumber><BinInt Length="4" Sign="NO" ByteOrder="BIGENDIAN"/>
<ValueRestrictions IgnoreCase="NO" Rule="INCLUDE"></ValueRestrictions>
</BinaryNumber>
</ITEM>
<ITEM SimpleTypeName="StrucId" CategoryOrItemParent="Field ROOT" partition="NO" OrderSubtypes="ASCENDING"><CharTextWestern><Size Min="4" Max="4"/>
<PadText Justify="LEFT" ApplyPad="ANYCONTEXT"><PadValue><SP></PadValue>
<PaddedToMinContent/>
</PadText>
<Western CharSet="NATIVE"/>
<ValueRestrictions IgnoreCase="NO" Rule="INCLUDE"></ValueRestrictions>
</CharTextWestern>
</ITEM>
<ITEM SimpleTypeName="StrucLength" CategoryOrItemParent="Field ROOT" partition="NO" OrderSubtypes="ASCENDING"><BinaryNumber><BinInt Length="4" Sign="NO" ByteOrder="BIGENDIAN"/>
<ValueRestrictions IgnoreCase="NO" Rule="INCLUDE"></ValueRestrictions>
</BinaryNumber>
</ITEM>
<ITEM SimpleTypeName="Version" CategoryOrItemParent="Field ROOT" partition="NO" OrderSubtypes="ASCENDING"><BinaryNumber><BinInt Length="4" Sign="NO" ByteOrder="BIGENDIAN"/>
<ValueRestrictions IgnoreCase="NO" Rule="INCLUDE"></ValueRestrictions>
</BinaryNumber>
</ITEM>
<GROUP SimpleTypeName="MQMessage" CategoryOrGroupParent="ROOT" OrderSubtypes="ASCENDING"><Sequence partition="NO"><Implicit/><SequenceComponent><RelativeTypeName>RFH2</RelativeTypeName>
<Range Min="1" Max="1"/>
</SequenceComponent>
<SequenceComponent><RelativeTypeName>Data Field</RelativeTypeName>
<Range Min="1" Max="1"/>
</SequenceComponent>
</Sequence>
</GROUP>
<GROUP SimpleTypeName="NameValuePair" CategoryOrGroupParent="ROOT" OrderSubtypes="ASCENDING"><Sequence partition="NO"><Implicit/><SequenceComponent SIZED="EXCLUDESELF"><RelativeTypeName>NameValueLength Field</RelativeTypeName>
<Range Min="1" Max="1"/>
</SequenceComponent>
<SequenceComponent><RelativeTypeName>NameValueData Field</RelativeTypeName>
<Range Min="1" Max="1"/>
</SequenceComponent>
</Sequence>
</GROUP>
<GROUP SimpleTypeName="jms" CategoryOrGroupParent="NameValuePair ROOT" OrderSubtypes="ASCENDING"><Sequence partition="NO"><Implicit/><SequenceComponent SIZED="EXCLUDESELF"><RelativeTypeName>NameValueLength Field</RelativeTypeName>
<Range Min="1" Max="1"/>
</SequenceComponent>
<SequenceComponent IDENTIFIER="ON"><RelativeTypeName>NameValueData Field</RelativeTypeName>
<Range Min="1" Max="1"/>
<Rule>LEFT ($,5) = "<jms>"</Rule>
</SequenceComponent>
</Sequence>
</GROUP>
<GROUP SimpleTypeName="mcd" CategoryOrGroupParent="NameValuePair ROOT" OrderSubtypes="ASCENDING"><Sequence partition="NO"><Implicit/><SequenceComponent SIZED="EXCLUDESELF"><RelativeTypeName>NameValueLength Field</RelativeTypeName>
<Range Min="1" Max="1"/>
</SequenceComponent>
<SequenceComponent IDENTIFIER="ON"><RelativeTypeName>NameValueData Field</RelativeTypeName>
<Range Min="1" Max="1"/>
<Rule>LEFT ($,5) = "<mcd>"</Rule>
</SequenceComponent>
</Sequence>
</GROUP>
<GROUP SimpleTypeName="usr" CategoryOrGroupParent="NameValuePair ROOT" OrderSubtypes="ASCENDING"><Sequence partition="NO"><Implicit/><SequenceComponent SIZED="EXCLUDESELF"><RelativeTypeName>NameValueLength Field</RelativeTypeName>
<Range Min="1" Max="1"/>
<Rule>$<1048576</Rule>
</SequenceComponent>
<SequenceComponent IDENTIFIER="ON"><RelativeTypeName>NameValueData Field</RelativeTypeName>
<Range Min="1" Max="1"/>
<Rule>LEFT ($,5) = "<usr>"</Rule>
</SequenceComponent>
</Sequence>
</GROUP>
<GROUP SimpleTypeName="RFH2" CategoryOrGroupParent="ROOT" OrderSubtypes="ASCENDING"><Sequence partition="NO"><Implicit/><SequenceComponent IDENTIFIER="ON"><RelativeTypeName>StrucId Field</RelativeTypeName>
<Range Min="1" Max="1"/>
<Rule>$="RFH"</Rule>
</SequenceComponent>
<SequenceComponent><RelativeTypeName>Version Field</RelativeTypeName>
<Range Min="1" Max="1"/>
<Rule>$=2</Rule>
</SequenceComponent>
<SequenceComponent><RelativeTypeName>StrucLength Field</RelativeTypeName>
<Range Min="1" Max="1"/>
</SequenceComponent>
<SequenceComponent><RelativeTypeName>Encoding Field</RelativeTypeName>
<Range Min="1" Max="1"/>
</SequenceComponent>
<SequenceComponent><RelativeTypeName>CodedCharSetID Field</RelativeTypeName>
<Range Min="1" Max="1"/>
</SequenceComponent>
<SequenceComponent><RelativeTypeName>Format Field</RelativeTypeName>
<Range Min="1" Max="1"/>
</SequenceComponent>
<SequenceComponent><RelativeTypeName>Flags Field</RelativeTypeName>
<Range Min="1" Max="1"/>
</SequenceComponent>
<SequenceComponent><RelativeTypeName>NameValueCCSID Field</RelativeTypeName>
<Range Min="1" Max="1"/>
</SequenceComponent>
<SequenceComponent><RelativeTypeName>mcd NameValuePair</RelativeTypeName>
<Range Min="0" Max="1"/>
</SequenceComponent>
<SequenceComponent><RelativeTypeName>jms NameValuePair</RelativeTypeName>
<Range Min="0" Max="1"/>
</SequenceComponent>
<SequenceComponent><RelativeTypeName>usr NameValuePair</RelativeTypeName>
<Range Min="0" Max="1"/>
</SequenceComponent>
</Sequence>
</GROUP>
</NEWTREE>
</TTMAKER>