Razer Carcharias with Built in Mac mic Will it work?

I recently bought the razer Carcharias and I was thinking I could hear and play better on World of Warcraft with the headset along with hearing better in vent. But I cannot get the headset to work. I'm not sure if It's cause I already got a built in mic or if there is no where to plug the mic in. Not sure if the symbol actually looks like a mic but I plugged it in. I think people got it working before I'm just not sure how to. Anything I need to change on vent or something to actualy get the mic working or does my built in mic/ Mac computer not compatible with the headset.