Asterisk, Voip, Billing

--Need billing Module and configuration of server. --I have: linux, asterisk, SER, Radius working NOW.... --I have: cam, voip client like skype working NOW.... --I have: enabled: for Cam, Sip Voip, Voicemail working NOW.... --I Need: expert for Billing Module, Call forwarding, PSTN working with [login to view URL] to install --I Need possible also: other work should be done that I am not aware of - please advise. NO PLACEHOLDER BIDS please --Possible billing solutions I found are: [login to view URL] [login to view URL] [login to view URL] --I require input and and what you think is best. I would give more consideration to those that in PMB stated what you think is best and why and advice on benefits and drawbacks of each. Including possible extra charges for extras and what they would be...