FLT and LAND ALT Displays

I built a B737 Overhead Panel using all Open Cockpits I/O boards and components. I have never been able to get my FLT and LAND ALT Displays to work with Prosim737 or otherwise. I can send different numbers to the displays using the SIOC Monitor so I know the inputs and outputs are correct in my script. The encoders show to be changing the numbers correctly in the IOCP Console but are not writing to the displays. I was wondering if anyone who has built an overhead panel has had any success with this using OC components or with any other manufacturers cards and software to control the FLT and LAND ALT Displays.

Jerry