I think that converence is a good way to do it, and it seem to be possible but I don´t know how to automate the process and integrate it in a2billing php code.
Creating a conference room in Elastix, inviting two extensions (one of them can be a sound-player) and calling out do work, but as we are forking to A2Billing it´s here where the thing must happen and not in elastix or asterisk i think.
The PHP code from a2billing is just too complex for me to make such a thing.
Imagine a customer that auth. via a valid calling card, than calls the outgoing number and the call begins, i just want to play a sound file so that the called person can hear it, or the two persons can hear it if it is a conference...
Hope anyone have an idea
Regards.