Just an update on the topic I posted a while back.. (VFX trunk not passing correct DDI / DID info to Trixbox)
I found the solution here.
Edit /etc/asterisk/extensions_custom.conf, and add the following two lines: [custom-get-did-from-sip]
exten => _.,1,Goto(from-trunk,${CUT(CUT(SIP_HEADER(To),@,1),:,2)},1)
Then edit the trunk, and add (among its other parameters):
context=custom-get-did-from-sip(Add this to the peer defintion, not under "User Context" or "Incoming")
Works a treat :)
D