V90 servo drives used with their native positioner are very simple, reductive.

To do what you have in mind, (although I have never done it), I would go and write a homing state machine where I would first of all go and disable the overtravel inputs, and leaving the reference one, then reduce the maximum current limit and start the homing procedure. (The PX would then have the homing function only.) Then when the procedure is complete, I would bring the axis to a known position out of the overtravel and finally reactivate the overtravel function, bringing the useful torque limit back to the desired nominal limit.

There is a little software writing involved, but it is not impossible and the axis does not go into overtravel error. Of course, you have to be sure you don't have any problems during homing with the overtravel off.