Here's the AdvanceMame script...
In your advmame.rc file, find the line that says script_video and change it to this:
script_video delay(50); simulate_key(key_o,50); delay(50); simulate_key(key_k,50); delay(50); simulate_key(key_o,50); delay(50); simulate_key(key_k,50); delay(50); simulate_key(key_o,50); delay(50); simulate_key(key_k,50); wait(!event()); set(kdb,0);
I can't remember where I found this, but it works great!