modifying Fanuc post definition?

Hi
I'm using HSMexpress on and old Fanuc 0m. I'm using the Fanuc.cps- generic Fanuc.
I need to add a G49 H00 before the tool change is called. I have been adding it manually after the G91 G28 Z retraction finishes on the G90.

can I add something like the following in the function onSection()

// retract to safe plane
retracted = true;
writeBlock(gFormat.format(28), gAbsIncModal.format(91), "Z" + xyzFormat.format(0)); // retract
writeBlock(gAbsIncModal.format(90));
writeBock(gFormat.format(49),hFormat.format(00)
forceXYZ();