In RPN scripting, aka, what AAO and SPAD is using to set variables, you would use the > symbol to set a variable. Because XML can’t handle that, it is written as > instead. RPN syntax of something like 1 (>L:variable_that_does_things) turns into 1 (>L:variable_that_does_things).
I took a look at this plane this morning. Have you tried using the event STARTER1_SET and STARTER2_SET for the starter? It’s a standard MSFS event, not a BVAR. Setting it to 1 seems to activate the starter and 0 stop it. 1 will actually move the switch animation to start but 0 won’t move the switch although it does seem to work. Not sure how SPAD does it, but in AAO I would use:
1 (>K:STARTER1_SET)
1 (>K:STARTER2_SET)
0 (>K:STARTER1_SET)
0 (>K:STARTER2_SET)
Devmode shows that the BVAR should be B:ENGINE_Starter_1, number) but I couldn’t get that to do anything but using the K event above works. I’m still checking the ignition for you.