You are running a distributor based ignition right now ? Or separate coils ?
You can twist the distributor a bit, and you should check anyway that the rotor is aligned to hit the corresponding posts in the cap at 20-30 BTDC to give a good spark.
You can change the trigger edge (falling vs rising) for the secondary trigger, it will then shift a large number of degrees depending on the width of the "window" that the trigger sensor sees. I'm not sure if it will appear earlier than the missing tooth gap, or later. You'll see and it would be cool if you posted the graphic view of that, you could also zip the triggerlog file and upload to vems.hu file area.
http://www.vems.hu/wiki/index.php?page=FileAreaOnly upgrade the firmware as a last resort, this should work.
If you want to try 1.1.84 firmware, make sure to use the latest nightly release :
http://www.vems.hu/download/VemsTune/NIGHTLY/VemsTune-Install-2010-11-04.exeI'm not confident with the stability of those releases of VemsTune, but it's required for this firmware since the introduction of a safety and immobilizer function in the firmware. The dev team is working on a new communication model, that'll turn out better.