Anyone ever fit bar ends to Ergon grips?

I have a pair of Ergon's "race" grips, seen here:

http://www.universalcycles.com/shopp...p?category=708

They feel absolutely wonderful & I can't wait to put some miles on them. I wish to remove the useless 'stubby' Ergon ends & put on my own (longer) ends. Problem is, I cannot find any bar ends that fit over the plastic inner clamping tube that the Ergon stubby's clamp on to (they have a considerably wider mounting ring than off the shelf bar ends).

Suggestions?