[Mobhack]

From my original post:

There is quite simply no sane way to write any form of conversion utility

It's up to you to do it manually. Multiply the SP3 map size by 5 and create a new map. Plot each SP3 hex into a 5x5 matrix of 50m hexes (you may want to lay out the flat WinSPMBT map in 5x5 grids of alternate colours - using, say long grass and plain).

Andy