Pete, thanks for your reply. I did al the tests you asked an everything is ok. Then I remembered that I deleted the elevator, trim, rudder and ailerons from my two-engine-prop-profile to see if the plane then would use the general-axes settings for these. It did not so I re-assigned all except I forgot the trim. I then tried the trim in a plane from another profile and that worked, but I noticed I had to turn the trim-wheel quite a while longer, before it would show up in the assignment sector of FSUIPC. So I went back in a two-engine-prop-profile plane. Took more time to turn the trim-wheel and it worked. All is fine now. Sorry for wasting your time with my un-patience.
Roy