PS - Only workaround I can find is to fire up P7, load a primitive, apply the image texture and export it as a Wavefront object. Then open P10 and import the .obj. This seems to work OK, but it would still be nice to not have to do that.

I tried exporting P10's primitive box as a .obj then re-importing it, but the texture still doesn't map to it correctly. The export/import method only seems to work with the P7 primitives.