Cant edit volume groove agent

Hi. I wonder if anyone can help me with a problem. Im a new cubase user and I have recorded a song and have used midi drums. But I cant change the volume of the drums in the mix consol. Even after I run dissolve parts so all the drums are on seperate tracks all the faders are in the bottom and I cant manually change the volume of any of the drums in the mix consol?
Any thoughts??