It is not possible to control the filter bank frequency via soft knobs or other controller! It is a missing feature, indeed! Please make it possible to change this issue. I will control and record the frequency of the filter bank. It is one of the highest dedicated, most dramatic change of a sound, I need it on my controller. There is no work around with Ableton so far 
Also mentioned here:
http://virus.info/forum/index.php?page=Thread&threadID=4001