wow, glad someone else has got it working, not sure how many people ever used this feature in VEMS, but I always thought it was a great feature.
Never got it working over firmware 1.1.89 though, which firmware are you using.
here is how to fix it for the time being, as there is an error in the location, I asked vems to fix it 2-3 years back, so good luck with it.
Find this file in the vems directory.
section-gpsdata.ini
open it up in wordpad.
look for this line and change it for the line below.
longitudeDec = { floorLong + ( longitude - floorLong ) / 60 * 100 -3.02653 }
then save the file and exit wordpad.
Load your vemstune and you should have a -3.02653 offset in the longitude gps, which should put your position correct.
Keep a copy of the file you changed, as everytime you load a new vemstune you will need to copy it back.
Not using my vems at the moment, as my v8 is getting another re-build due to it dropping a liner, hopefully back on the road this summer though, good luck and hope it all works for you.
Keep me posted about the error report and I hope they do fit it this time.
regards
scott
