GSM.h for Sim900?

Hi, I'm using a GSM shield with the Sim900 chip and I was wondering if the GSM.h library would work with it or if there was any good alternative. Specifically I need the GSM and GSMVoiceCall classes or an equivalent. I know its incompatible with SoftwareSerial but I'm using AltSoftSerial instead.

EDIT: I think I may have found a solution, I'll check it out.