ong83,
Calls made via the AA need a route to make the outgoing call.
You can set it up a number of different ways. Every approach ends up either using a properly configured trunk or you get the "no service available" message from the OBiMAN voice. Here a a few metods:
1) Set up the speed dial in a way where you hardcode the service (trunk) you want to force the call through.
**x5145551212 (**x could be 1=sp1, 2=sp2, 8=PSTN, 9=OBi)
2) Set up the AA to automatically chose a preselected trunk
Voice Services->Auto Attendant->Auto Attendant->PrimaryLine =(whatever)
Of course choose a trunk which is enabled and registered/connected with the voip service (or PSTN service) you entend to use to make the call with.