There's a thread on this forum that covers this in depth:
http://www.blackberryforums.com/bes-...tion-push.html
I've had mixed success white listing applications on our 4.0.4.5 Exchange BES. The biggest challenge I've yet to beat is supporting multiple Blackberry models for the Google Maps application. After weeks of going back and forth with TSupport, they don't have it licked yet either. I still have people there trying to help me with this so I'm not giving up hope yet.
IMHO, there are greater issues to address for BES security than white listing certain 3rd party applications, but I also believe that this is a far more popular issue in the Enterprise than RIM is currently giving it credit to be.