To add 855, look up and copy what you have set up for 1800 numbers in LD 90. It could be in a couple of places, depending on your set up.
Most likely:
REQ prt
CUST 0
FEAT net
TRAN ac1
TYPE npa (or SPN here)
NPA 1800
When this prints out, basically you duplicate the information for the 1855 number.
REQ new
CUST 0
FEAT net
TRAN ac1
TYPE npa (or spn here)
NPA 1855
Adding the next few options to mimic your print out for your 1800 numbers.
Outbound name will depend on the set up you have, types of circuits etc and the way the telco has them programmed. It may be something the telco has to do on their end.