For now, not having a direct solution, you could map your keys such as F5, F6, F7,F8 to do the same thing.
There is no intellgence between mapping and the grids but you could do something like:
alias F5 ix -5
alias F6 ix 5
alias F7 iy -5
alias F8 iy 5
Writing a wrapper in skill to assign the keys that way is not difficult. I have never tried to intercept the arrow keys so I am not sure if they can be intercepted or not.