Did you read this article? We will start at point 12 where we now will address the function of the Trim Wheel on the Saitek Multi Panel.
You should have had enough exercise with the previous configurations, so activate SPAD and get to the Trim page as in the image below. Set the acceleration slider to Max.
In FSUIPC set 64,6 to Elev Trim Dn and set 64,8 to Elev Trim Up
In both cases check the box Control to repeat while held
Done. Check the working in the Cockpit – Center Pedestal View