Hi, Max!
I remember times when MULTIPLEX/Hitec offered Hitec-servos that could be programmed with the MULTIMATE but it was only one serie. For the programmable Hitec-servos you can buy a special gadget. unfortunaltely it costs about 90 €.
As far as I know servos can't be programmed by the MULTIPLEX-launcher.
If you don't want to buy the little Hitec-programmer (if it is only for this one purpose) you should ask you dealer or some club-mate for help.
There or also little devices on the market that are fit in between the receiver and the servo to inverse the servo.
with regards
profimc