[Asterisk-Users] Polycom digitmap question

[asterisk at txpe.net]

via google, I found the reference regarding digit maps for the Polycom phones:
http://lists.digium.com/pipermail/asterisk-users/2005-January/082884.html

But I don't see any instruction for prepending digits to the number 
dialed.  Does anyone know how to prepend a digit to the number dialed (from 
the Polycom side, not Asterisk)? I can do this pretty easily on a Sipura. 
i.e. Say I want to add the digit "9" to what the user dials 1xxxxxxxxxx, 
the Polycom should actually send 91xxxxxxxxxx to Asterisk.