Using UR242 with amplitube.

I have a small problem when i try to use Amplitube through my UR242 Interface.
when i open make a new instrument or recording track in Cubase the Yamaha preamp from the UR242 is the first thing i can hear. But as i load up Amplitube as an VST the Yamaha preamp seems to interfear with the VST and the sound from the both of them get mixed, I have tried to turn down the input devels on the Yamaha mixer separate from Cubase, but this only brings down the levels for both the Yamaha preamp, and Amplitube. Is there any way to turn down the Yamaha preamp Without losing sound from the Amplitube plug-in?