I agree that this is currently almost impossible on the Warthog throttle. I've remapped the TDC depress to another button which solves it. Having said that, I do like the thinking behind it. I'm finding it easier for the MAV to lock onto my intended target compared to the way the MAVs work with the A-10C.
As an aside, I find the overall operation of the Bug to be much more straightforward / intuitive than the Hog!