HDCP is broken by surround from what I can tell. I have tried 2 different sets of monitors in the past, all of which were HDCP compliant, and none of them worked in surround, but all of them worked in "Activate all displays" mode for watching Blu-Rays. I've tried both PowerDVD and WinDVD. You can use a program called "AnyDVD" to bypass HDCP protection to play movies without disabling surround, but it isn't free.
AnyDVD works good. Just put the Blu-ray into your computer, navigate to the m2ts file on the disc and play it in VLC in realtime from the disc. I do not condone movie piracy, but using AnyDVD with the original Blu-ray disc to allow proper playback off of the original media I find to be ethical.