midi mapping for the numeric 0/rest

I believe this is not currently available.
My normal mode of note input:
is right hand on the numeric keypad (note duration)
left hand over the alpha characters (note pitch)
This had been fine as I don't input much . But lately the creation of scores has escelated.
I have added a UMK49 keyboard.
I have remapped the the last "octave" of keys to the numeric(or note durations) (right hand) and use the rest of the keys for note pitch input.(left hand)

The only thing that bugs me at the moment is my preferred way of inputting rests.
I set duration then hit zero.
midi mapping currently does not have a way of setting a midi note to the numeric "0"
or am i missing something?
Yes I can map a midinote to "rest" but then that requires me to remove my hands from the UMK49 and onto the mouse to enter.

BTW loving the new ver4.0 your hard work is much appreciated.