From our lead systems engineer:
"To use the new force trim option use the AMS and click on the new "Controls" section for the 530, and assign a key or button to the force trim trigger.
When you are in the cockpit, you must enable the force trim by using the two previously unused switches labelled OVSPD TEST and FAULT TEST. (picture below.) The one on the left turns on the force trim system when in the Up position. The one on the right enables the force trim to work with the rudder too when UP.
With a key assigned in AMS and both switches up, a press on the force trim button will make the current cyclic and rudder petal settings the new center point. Thus as soon as you press force trim, return the joystick (and rudder if you have that switch up) to the neutral position. The helicopter should retain its current trim. You can use force trim as often as you'd like.
In case you are unfamiliar with it: Force Trim is not an autopilot! Be sure the helicopter is in a stable condition when you push the button. If it's rotating or banking, you'll simply lock in that trend and have to fight it. (This is how it really works, it takes some getting used to.)
This can take a great deal of the work out of flying. The real MD530 did not have a force trim, we're adding it as a optional "quality of life" enhancement.