Oberheim checksum needed

Hi, for setting global parameter changes from the E1 into a Oberheim Matrix 6/6R/1000, a checksum is needed. I find no info on how the checksum is made.
What I know is that the Master Parameter Data Message is constructed as follows:
F0H 10H 06 03H <version> <data> <checksum> F7H

  • <version> = 03H for Matrix-1000 , and I believe it to remain blank for Matrix 6
  • <data> = parameter number (00-57), followed by value byte
  • <checksum> = checksum of packed <data>

Does anyone know how to make the checksum?

Source of the parameter number I found here (not verified), in appendix E: