Problem with multiple midi programs

Hi newbe here…i am trying to set up one midi player with multiple programs on different channels…problem is I am not being able to use anyother channel except channel 1. so if i use halion se or sampletank channel 2 on up is useless…in the side chain I dont see where i can set a midi channel number 2,3,4,etc…what am I doing wrong?..lastly I got an audio track…and on it my vocals…on on section I would like to lower the volume of one note…so it aint that loud…how would I beable to perform this? melodyne it was easy to do…but all I seem to be able to do is move it up or stretch it in cubase…can anyone please assist…I think I saw how to do this in a video but cant locate the video.

thank you