495811 Asterisk FreePBX Vitiger Integration

I am looking for an Asterisk developer or programmer that is familiar with vtiger and knows how to integrate and write custom code to identify the customer that call in to identify and capture its name phone number address details into vtiger and also use the functionality of any of the the pbx either elastix or trixbox or Free PBX which ever you feel has most of the features and then integrate and install a2billing to track the billing charges of the inbound or outbound call that will be done within vtiger itself .