Default email service

[MB43]

I have both a BES and BIS account on my BB8820. Under Advance options I have selected Desktop (ie. BES) as my default. However, when I compose a new message, eventhough it says "Send Using: [Default]", unless I go and change it to desktop (instead of default), it sends the message from the BIS account.

Any ideas why my defult is messed up?

Thanks.