signature validation on secure edit messages

Jeez. I really don't know why the heck this always happens to me, my digsigs not validating. You can finger me at tjbryce@amherst.edu to retrieve a message with a valid signature. I always write the message in eudora, copy it, sign it in MacPGP as TEXT with attached signature, then go back and paste it over the old message. Then I go back to MacPGP and check the signature on the clipboard to be sure - no problems. But after getting mailed, it doesn't work. Damn. Tom