Custom battles aren't really a problem at the moment... Nobody downloaded EB just so they could look at the pretty units in custom battle... And the EB team didn't make it just for that... Enjoy the years worth (?) of scripting that has gone into the campaign and all the new units and buildings and features... I know i am...

And to the EB team... Make custom battles the last thing on your list to fix... Almost everyone who plays the mod isn't too bothered about custom battles since we're all in love with the new features in the campaign...