Maybe it would help to explain why you want to do this? It seems it would be much easier to just route point to point in the 3D file than try to make a netlist manually (which would connect the points also, but seems harder?)
Clearly we need to do a MUCH better job documenting the netlist stuff for those that don't wanto to use an out of the box ECAD integration. The best I could find was a PPT from 2005 (!) that on slide 32 or so gives some examples. Hopefully this is of use to you. We will be looking at how to improve our docs in this area.