How to disable or control Twistbones in Control Rig

Hi,

Ich have following problem:

I rigged my character in Accurig and imported it into unreal engine. so far so good. I set up the control rig with a IK chain for the left arm. It works but the twist bones do not copy the rotation of the main bone so it looks crooked. When I set up a rotation constrain it still does not work. this is how it looks:

I hope somebody can help me here. I looked through a bunch of tutorials but couldn’t get it to work. If the question came already up I appologize and would appreciate a link to the respective thread. I didn’t find anything on the topic, sorry if this is redunant.

all the best.