Wieder auf englisch, wie im anderen thread:
To include a full blown controller functionality (programmable, customizable etc) is at this point unfortunately impossible.
Please consider using a cheap dedicated Midi Controller for this and hooking it up somehow with the Zaquencer´s Midi through capability.
What´s already possible now are the 2 Midi controls Alpha & Beta (can be CC, Aftertouch, Program change, Pitch bend – set in the global menu). If you don´t use them for sequenced Midi Control Changes, you can set them all to the same value and then hold the button to affect all steps at once. This way you have two live tweakable Midi controls for every track!