GSM calls via VoIP

I need to integrate "2N VoiceBlue Enterprise 4 GSM" (GSM-GateWay) in my VoIP (Asterisk) system. I have a Linux server with Asterisk installed with WAN and LAN ethernet interfaces & Digium Card in it. I want to transfer my calls from GSM to VoIP and other way, callback with provided dialtone to be able to enter a phone number & make a call in conference mode through GSM to IP. For all other technical questions you can ask me in PM. I will provide you all remoute access to my system, such as SSH-login, VPN, etc.