Cubase 6.5, Yamaha N12 mixing desk and a Sherman Filterbank2

I recently purchased a Sherman Filter bank and i wanted to hook it up to my Yamaha N12 Mixing desk, and through Cubase 6.5, i can use it perfectly on my keyboards and analogue synths but i just can’t get it to work through a audio channel on the desk and through Cubase i have an insert cable 1/4 in TRS to Dual 1/4 in TS which i connect the send into the signal in on the sherman filterbank and the return on the main out which then goes to the insert into channel 1 (for example) using the DAW i can not get to manipulate the sound or use the sherman filterbank, has any one got any ideas what i am doing wrong? all i would like to do is to filter a channel on my desk with the filter bank but what ever i try i can just not get it to work! aaaarrrrrrrrrrrhhhhhhhhhhhhhh

any thoughts or help would be greatly appreciated

all the best