I just used an existing address that I could sign from instead of the "sending address" off blockchain.info. Technically, a Bitcoin transaction doesn't really have a sending address. It's just easier to understand it that way.
Please do not do this. The sending address from the TX is what is used to verify the signature.
For clarity, should we send you the first sending address in the email when the transaction has multiple sending addresses?
I can send updated emails if you need them for bookkeeping purposes.
Thanks.