I just dealt with this issue. The fix linked is fine if you are not a Blackberry user with elevated domain access (such as being a Domain Admin). RIM would love for you to just remove your elevated access and use some other account, psha right.
AdminSDHolder permissions will remove Send As from any user with elevated access. DSACLS can be used to correct this. This used to be in the MS KB, but it was removed in revised version.
Run this, wait about 2 hours, restart your BES Router Service, and you should be good
This, combined with granted Send As to your besadminuser (and making sure that user itself has no elevated access, it doesn't need it anyway for BES purposes) will fix you up good.