Sorry guys, was out this weekend, missed this thread.
@Guomindong: you don't want to edit AI.ini because those are global parameters. Well, unless you want to make global changes

You were correct, explosion radius for each missile
is inside
Rockets.xml. However, you must look at the detonator's radius instead of the one for the missile. Each missile has a definition and a detonation, that's how they work. For easy stuff like damage and radius you just edit the detonation. You can refer to
this post here or the other posts in
that thread.
I was working on some "bowling ball" missiles which bump a ship far away instead of inflicting much damage, but it got funny and weird when you kick capital ships away lol.