Download LJ_Cmder from this site. Install on your PC.
Connect your BB and run JL_Cmder.
Once running use 'Reset to Factory' option.
This will not wipe the OS. This will remove the IT policy and unlock the firewall. This in turn should remove the need to use BES. You can then remove anything to do with the BES.
I cannot tell you the options part as I have removed it alread from my phone so cannot find anything to do with BES.
Pin - 20683AD4
If at first you do succeed, try not to look so astonished.
Children need to feel secure, so strap them down whenever possible.