I don't see a reason why you wouldn't be able to do that. As far as I know, the ethereum signature is considered to be as collisionless for current regular computers. I'd give it a try anyway and see how it goes, they should be able to verify it fairly easily. It might take a bit longer for them to do it as they will mainly be using Bitcoin.

Resend your request to Cyrus (not Theymos) in the format Theymos gave on his thread (that has been quoted above on this thread). Follow the rest of the instructions from there (using a ethereum address/signature instead of bitcoin).