Fusion PBX and a ASTPP Billing System integration

We have made lots of changes to this softswitch and wants to integrate both so that calls from FusionPBX can go through ASTPP billing and ASTPP will bill the calls. You must be knowledgeable in Freeswitch as the system is a combination of two popular programs merged together. Start allowing registration of devices, providers, authentications etc – this means one can configure DIDs, map them to a provider, run calls origination and termination, register IP phones etc. We only want developers who are knowledgeable in FusionPBX and ASTBB and have worked on these systems before with results. We will use these systems as a yardstick to measuring how good the best candidate will be. This is the interface as we have merged both at the moment but needs the integration for call flow like: [login to view URL] 1. session linking in gui. 2. having use proper pbx in gui 3. call not approaching with proper pbx handling. 4. having issue in core integration gui. like provider, active calls, gateways etc