Signatures

Hi
I'm trying to set up my email signatures. I have two accounts, call them A
and B. I want Account A to be the default account and have no text attached.
I want B to have the signature I've created.

The problem is that if you leave the default signature box empty, a prompt
message pops up telling you to insert text and it won't let you leave it
blank...anyone figured this out?

thanks

Chris