I have a 2011 5.7 limited and I did this when I first bought car about a year ago. Memory is a little hazy but i'm pretty sure this was what i did. i'd assume it would work for the srt8 also, hopefully.
Fasten seatbelt with engine off
Unfasten and fasten seatbelt 3 times and end with setbelt fastened
Start car again with seatbelt fastened
Hope it works, all it does is trick the sensors. If i leave my engine on and step out of vehicle, the chime will go off. But when i am in it, no chime