OSX mail keeps on starting up, pls help?

Hey guys / gals,

This morning I purchased Mac:Office and configured Outlook to work with my Exchange server. Previously I had OSX Mail do the same. iCal was connected to Exchange as well, as was my address book.

I know, it's a bit like surrendering to the dark side, but at the risk of starting a flame here: there's just no functional equivalent...

Switched iCal and Mail and Adress book off (they don't start at login anymore).

Removed them from their permanent Dock positions.

Removed the Mail account for Exchange.

Removed the iCal account for Exchange.

Removed the Addressbook account for Exchange.

Removed the settings to sync with iCloud for email, calendar and contacts.

Configured Mac:Outlook and that works.

Configured Outlook to be default mail client.

My default RSS client is and has been NetNewsWire Lite.

Now, still, when I shut down Apple Mail, within 15 or 20 seconds, it starts again.

What am I missing here?

Gerard