DM800HD SE - Twin Tuner

I recently purchased DM800HD SE - works fine but I want to install a twin tune so that watch one channel and record another.... I have searched the web and even bought one (BSBE2-801A) but when its plugged in the DM800 HD SE, the box will not turn on. So I have restalled the original single tumer and the box works fine.

Is there a twin tuner for DM800 HD SE... or would I need to buy something like Vu+ Duo...

Any help guidance would be appreciated...