A push button start does not disable the security system. The push button start simply uses the RFID chip in the key to start the car, all a push button start is, is another layer of complexity.

Your only recourse is to pull the ECU, SKREEM and lock cylinder and send them all to Josh in California - in a few days, he will send it all back with one or two keys, cut an programmed to the car.
He also offers a "SKREEM disable" which means you only need a key cut to the lock cylinder - but stealing the car gets kinda easy if you do that.

Josh is a Crossfire owner and forum member, call him:
https://themercedesswapshop.com/