jp8080 checksum for ctrlr panel

[msepsis]

I'm building a jp8080 ctrlr panel and am stuck on how to program the checksum for a panel for this synth.

I can program my knobs, sliders, buttons and dropdowns to send a sysex parameter change, for instance control Mono sends:
f0 41 10 00 06 12 01 00 40 47 01 77 f7 (01=on, checksum is 77) and
f0 41 10 00 06 12 01 00 40 47 00 78 f7 (00=off, checksum is 78)

however there is no way for me to program that checksum - can the checksums be figured on the fly??

I'm using the cross-platform application http://www.ctrlr.org