[Freeswitch-users] Help required for integratrion of "Mod Nibblebill" in FreeSwitch

Hi, We have integrated our IVR application with FreeSwitch by HTTAPI and make phone calls via DIAL HTTAPI command through Nexmo services. Its working fine now and we are able to make a phone call via Nexmo Gateways. But we need to integrate Billing of phone call in our IVR application now. I have heard about "Mod Nibblebill" in FreeSwich for controlling calls duration and making billing to a customer. If we can make billing process by "Mod Nibblebill" then please let me know some more useful information about "Mod Nibblebill" and how can we integrate it in FreeSwitch with Nexmo Gateway. Thanks, Regards, Manish Talwar