Cubase 6, EZdrummer and Alesis MD6, not working...

Hi, i got a strange problem. I cant get my Alesis MD6 to work with EZdrummer or Cubase 6. Well, it works for about 20 seconds, hear the sounds of the different kits in ezdrummer, see the signal in the mixer etc. But then it goes silent! No more signal. So what is going on?
I first turn on my Alesis MD6, set the GM format enableing contact with the computer and trigger function. I then open cubase. Make a new project. Add vst instrument, choose ezdrummer. I choose e-drum as audio in, and ezdrummer as audio out. And this process works for about 20 seconds. All is fine those few secounds before all goes silent, both sounds and signal. Isnt this strange? Anybody got some advice?


Can you hear sounds from different sources such as HALion?

Yes, Halion works just fine. But anything i try with the drum set won´t work. Groove agent responds as ezdrummer and works for 20 seconds. And the strange thing is that the internal microphone is activated during the process of setting up alesis and ezdrummer.