I use Chimex (Link Below) to override the seatbelts. $20.00 each and I red Plastidiped over the part where you hold it and cut off the wires. Chimex - CravenSpeed Online
Mine came with a plugin to put in the seatbelt wiring. You can also just get a belt buckle clasp off eBay to plug in to the seat belt when no one is in the seat. I got one for a dollar.
It just plugs in to the seatbelt harness, very simple. It was free with the emulator and works, but after I plugged it in the brake lights would stay on after the car was off if you turned the car off holding the brakes. Not sure how they are linked but after I took it off the car stopped doing that. Again since it was free I don't care, might have been a bad one. I don't mind spending the dollar for the clasp to put in the belt buckle receiver.
I even emailed srsdrive (ebay seller) about the seat belt sensor issue and they offered to send me a replacement or the belt buckle clasp for free. Very stand up seller.