Here is something I captured from SysMonitor that might shed some light on stuff, when 6 is pressed:
2251430357mS CMExtnRx: v=5074, p1=0
CMSetup
Line: type=IPLine 250 Call: lid=261 id=12830 in=0
Called[?Terri Lowe] Type=Voicemail (102) Reason=CMDRdirect Called SubAddress[mooh] Calling[5074] Type=Internal Plan=Default
IE CMIECallingPartyName (110) Joe
IE CMIECallingPartyKName (226) Joe
IE CMIEFastStartInfoData (6)
2251430358mS CMTARGET: 261.12830.0 3379 Joe.0: Setting Hard Timer 10000
2251430358mS CMTARGET: 261.12830.0 3379 Joe.0: LOOKUP CALL ROUTE: type=102 called_party=?Joe sub=mooh calling=5074 in=0 complete=0 ses=0
2251430358mS CMTARGET: OUTGOING CALL ROUTE
2251430359mS CMTARGET: 261.12830.0 3379 Joe.0: ADD TARGET (N): number=?Joe type=102 depth=1 nobar=1 setorig=1 ses=0
2251430359mS CMTARGET: 261.12830.0 3379 Joe.0: ADD VOICEMAIL TARGET
2251430360mS CMMap: a=3.9 b=0.0 Mapper::AllocateCodec allocated CMRTVocoder resource busy 1, total 8
2251430363mS CMTARGET: 261.12830.0 3379 Joe.0: ADD VOICEMAIL TARGET: SUCCEEDED
2251430363mS CMTARGET: 261.12830.0 3379 Joe.0: CancelTimer CMTCDelayedProcessing
2251430364mS CMTARGET: 261.12830.0 3379 Joe.0: INITIAL TARGETING SUCCEEDED
2251430364mS CMTARGET: 261.12830.0 3379 Joe.0: GetNoAnswerTimer:15
2251430369mS CMExtnTx: v=5074, p1=0
CMSetupAck
Line: type=IPLine 250 Call: lid=261 id=12830 in=0
IE CMIEFastStartInfoData (6)
Timed: 25/11/08 15:23
2251430370mS CMExtnTx: v=5074, p1=8010
CMFacility
Line: type=IPLine 250 Call: lid=261 id=7 in=1
IE CMIEFastStartInfoData (6)
2251430372mS CMTARGET: TargetOnProgress: res: 1
2251430374mS CMLineTx: v=10
CMSetup
Line: type=IPLine 10 Call: lid=0 id=12832 in=0
Called[] Type=Voicemail (102) Reason=CMDRX_MailboxAccess Called SubAddress[mooh] SndComp Calling[5074] Type=Internal Plan=Default
IE CMIECallingPartyName (110) Joe
IE CMIECallingPartyKName (226) Joe
IE CMIERespondingPartyName (228) Joe
IE CMIERespondingPartyKName (229) Joe
IE CMIERespondingPartyNumber (230)(P:100 S:100 T:101 N:100 R:4) number=5074
IE CMIEDeviceDetail (231) LOCALE=enu HW=8 VER=4 class=CMDeviceH323Phone type=33 number=8010 channel=0 gain=32
IE CMIESupplementaryService (3)
Network Facility Extension
sourceEntity: 0
destinationEntity: 0
Interpretation APDU
discardAnyUnrecognisedInvokePdu
CallingName.Invoke.CodePageUtf8String
invokeId 16131
user 'Joe' presentation Allowed
IE CMIEFastStartInfoData (6)
IE CMIECallSignalChannelData (8) unknown
Display [++fk?Joe]
Timed: 25/11/08 15:23
Locale: enu
2251430379mS CD: CALL: 261.12830.0 State=0 Cut=0 Music=0.0 Aend="Joe(5074)" (0.0) Bend="" [Line 10] (0.0) CalledNum=?Joe () CallingNum=5074 (Joe) Internal=0 Time=30 AState=7
-Ed