let it transfer them as read only then run a batch program to change them from read only
You can't transfer items when the disk is read only, its write protected, you cannot copy to it

If you can't disable Bitlocker in the Control Panel, then it's odds on you won't have the necessary priveleges to edit the registry either.
Why not just boot the laptop from a live *nix CD?
That way you aren't interfering with the operation of the laptop in any way, shape or form....and hence can't be in breach of any T&C's as far as the IT equipment is concerned 
I have full admin rights, if I knew what registry command to run, it would work....
How about copying your porn stash holiday snaps to dropbox then you can move em anywhere you wish.
While I'm a big fan of dropbox, its not suitable for uploading 4.5Gb!
Like Jimbob said, be careful about the legalities of disabling any encryption software. Even the NHS trust I work for has strict disciplinary protocols against disabling or using a non encrypted device within their network.
Not worried about that, my previous XP laptop was heavily modified from its original shipped state
