Hi Rob, I actually just deployed BBM 5.0.0.57 tonight via BES 5.0.1 to my 8350i phones.

I used blackberry's website to install the app onto a test phone, I then used (Blackberry Master Control Program) to great a ALX/JAD/COD zip file i loaded on my BES server. It took about 8-10 minutes OTA to install and prompts the user to Reboot now or Later on the phone.

If you are interested, shoot me an email/private message and I can try and help.