I've moved this thread to Ace Script Request. Please be sure to post your threads in the correct forum next time. Thank you.
Tech Support is for getting the editors to run, not for How-to-do some game development problem. Those go either to Ace support or Script requests, in this case to script request because you need scripts to change that.
The easiest way is probably a splash screen script that replaces the title screen with a map, or a script that places a map as the background for the titlescreen. Both exist for Ace.