Sorry, you are out of luck there. But you could just re-wire the R buttons and L buttons inside the MAS.

If you really wanted to get creative, you could get a QPQT switch (4 pole 4 throw) switch, and connect both the L and R button wires to it. This would make the L1 and L2 switch to R1 and R2 when you toggle the switch (mount it to the outside of the MAS).