You can simply re-map the escape key.
Actually, I just re-mapped the shifted 2 key away from escape to p2 start. That way when P2 hits the button to start, it starts whether P1 is hitting his button at the same time or not.
I like to use the command line tools via ctrl-alt-P. There are instructions posted at ultimarc's website telling how to program shift functions.
I can never remember exactly what you type to re-map the keys, or I'd be happy to tell you here.