Hi kukkos
I dont know if it is possible to install a detonation counter from RS250 on a MC28.
But for sure these links will help you a lot as they have all the counter working progress with many informations and installation guide but for the RS250 harness.

http://www.rscycles.com/images/hrc_spec_tools/Detonation_counter.pdf
http://www.nsr250.net/HRC_tech_notes/HRC_Settings%20using%20detonation%20counters.pdf

I think that these informations of the Nm torques and set up progress are very helpfull to understand how the all system works and were to pay attention,and give you a good start point for your modify project.

Wish you good results from Greece.