Callback with Asterisk and A2billing

I need an experienced Asterisk programmer to create a call back and calling card system with Asterisk, MySQL and A2billing on analog phone lines. Linux, Asterisk, MySQL and telephony card are already installed on my server. I have more detailed information that i will give about my needs. Call back The call back system receives the CID of the user and calls him back. Then the caller dials the number he wants to reach. Alternatively, the user could send an email indicating the number he wants to reach. Asterisk will evaluate this number and choose one of the 3 following ways to perform the call : 1. a local call : performs a 3-way calling 2. a long distance call in North America : performs a cc 3. an International Long distance call : performs a 3-way calling with the getaway of my VoIP provider. The users must also be able access the following functions: - goto a main menu - refer a new client by dialing his phone number - indicate the phone number of a referrer (if any) - choose language - create a new speed dialing entry in his phonebook and record its name - speed dial - play the recorded names in is phonebook - to be added to a waiting list if there are no available channels for long distance calling - call my company The call back system must be able to adjust the lenth of the delay before calling back and to play the greeting message indicated in MySQL for that user. This system must also be integrated with A2billing that will offer a customer and a Web administration interface. Two hours of training will also be required for A2billing. I can also consider having a tailor made Web administration interface for the users if you think that A2billing is not appropriate. Calling card The exact same script will be used for the calling card exept : there will be no calling back, there will be caller ID Based and PIN Based authentication, local calls will not be available. I will provide complete detailed description of the project that I have done on Microsoft Visio.