PDU to send SMS from a V620

I am having trouble constructing the right PDU for a Motorola V620. I
am writing a VB6 program to send SMS messages via my PC.

I can create the Hex text for the message part of the PDU. My problem
is the construction of Phone Number I am sending to and anything else
that comes before the message. I have some information on
construction SMS PDU for the Ericsson but Motorola is reluctant to give
any technical information about their phone?
Can anyone help please?

regards
george