Interesting... yes, I do see multiple on the left, each one with a different amount of BTC (when viewing in 'advanced' mode)... I may have to wait until I get home, so I can actually see the multiple addresses I have on my client. I assume I should be able to match up one of these addresses with an address I see on my bitcoin client/wallet?
Thanks for the help
All the sending addresses are your addresses. You have the private keys to all of them, so you can sign a message from all of them.