You will need to add the mcSoftLimitSetState command in the screen load script. (This is accessed from the screen editor)
this command is an as per axis command, so for example if you only needed soft limits for axis 0 (X) then you would use mc.mcSoftLimitSetState(inst, 0, 1)
inst = our controller instance
0 = our axis number
1 = on and 0 = off
mc.mcSoftLimitSetState(inst, 0, 1)
mc.mcSoftLimitSetState(inst, 1, 1)
mc.mcSoftLimitSetState(inst, 2, 1)
this would turn on XYZ on my machine.
mc.mcSoftLimitSetState(inst, 0, 0)
mc.mcSoftLimitSetState(inst, 1, 0)
mc.mcSoftLimitSetState(inst, 2, 0)
and this would turn them back off
DazTheGas