Before starting to edit your vertices, extract a copy of the mdl0 and do the same procedure of deleting all the model parts except for the one you are editing.
instead of changing the numbers to 0's, change them to 42F00000. this puts all the vertices for unused parts at 120 120 120 or something.
save the MDL0, convert it with William's converter, and use meshlab to convert it to .3ds
Now, open you vertices model (the one you make in this tut, not the one made with will's converter)
go to model, import, now import the 3ds from meshlab. change the view to Top
next select the model (not in vertex mode) DO NOT MOVE IT, ROTATE IT, OR RESIZE IT.
go to build, mirror. mirror on the X axis.
delete the non mirrored copy, without moving, rotating, or resizing the mirrored one.
now, select the mirroed one, hit control x and go to object, and select the first model there. this should be the vertex one. just paste now.
The william's converted model, should match up with vertices for the model converted through my method. now when moving points, only use the group select too, and not the individual point select, because it wont move the vertices together. follow the rest of the guide after this...
If deleting the model after mirroring is hard, before mirroring it, hit left 10 times, to move it left, then without changing any camera things, or window size, mirror it, delete the origingal, highlight the mirrored one, and hit left 10 times again to move it to the center