A2billing and Trixbox

I have trixbox and a2b running. There is some fine tuning I need to make. SIP/IAX extensions created in a2b are not getting a trunk for dial-out. I get CHANUNAVAIL, even though calls via PIN can get to make outbound calls. I am using context custom-a2billing for SIP/IAX and custom-callingcard for PIN calls. Both are configured as agi-conf1 and agi-conf2 in a2billing.conf. 1) I need to have these 12b SIP/IAX extensions making outbound calls. 2) I also want to create Extensions in Trixbox and contextualize them to custom-a2billing, so that they can behave as prepaid extensions the exact same way a2b extensions (SIP or IAX) behave. These trixbox extensions will have different names, since I do not want to name them after the PIN number created by a2b. 3) I need to have DID provisioning automated. I created a couple of DIDs but was not able to have one extension (via a2b customer site) assign itself with one DID Thanks Clovis