I'm relatively new to midi. I'm trying to create a custom interface for my S90. I have almost everything set up except I'm having trouble figuring out how to add a control for tempo control. in my documentation, I don't have a control number defined for arp tempo, though the on/off is there. I've heard other alluding to impilimenting something like this, but I haven't found anything yet.. any hints or pro-tips?