Once you make the new MAPI profile, you will probably still get the working state. Keep the BlackBerry unconnected, open desktop manager, go into options and mail profile settings (i think that's it, have intenet install here at home, so i don't have that option) and select the new profile. Close Desktop Manager, and reopen it.
If that doesn't work, close desktop manager, open the mail icon in control panel, click show profiles, and at the bottom, select "use this profile when outlook opens" and choose the new profile. Then delete the following directory...
"c:\documents and settings\<username>\application data\Research In Motion"
it'll be recreated next time you start Desktop manager.
Don't forget to set the default mail profile for outlook back to the original (in the mail icon in control panel, show profiles, at the bottom, select the other profile)