Well, I've tried everything I can think of off-hand. Apparently you can't change the defaults... all you can do is either have heroes as they are, or turn them off completely.
Unless there's some new command I haven't tried. I tried making up a few like the following:
...none of which seem to help.
Oh well... sorry!
Guess you'll have to wait for the full version to have your dream server, unless somebody else knows how (through commands)!
So I guess just use this:
"C:\Program Files\LucasArts\Star Wars Battlefront II Beta\GameData\BattlefrontIIEngBeta.exe" /autonet listen /resolution 1280 1024 /throttle 256 /gamename [SBF]DannBoeing /playerlimit 50 /noaim /adminpw <yourpasswordhere!> /playercount 0 /noteamdamage /sideselect /bots 4 /difficulty 3 /spawn 3 tan1g_con 200 200 uta1g_con 200 200 tan1c_con 200 200 uta1c_con 200 200 uta1g_1flag 200 200 tan1c_1flag 200 200 spa1g_ass 200 200 spa1g_1flag 200 200