Ok Im going to have to retract that last statement that this is possible! It isnt reasonably possible - at least not as far as my experimentation with this went. There is massive difference in the scale between Wings units and Sketch-Up's. Even after scaling the sketch-up model down to 1:400 so that it would actually be able to be displayed by wings (it doesnt fit the camera view parameters otherwise) when I merge the wings model of my pylon it is tiny next to the place holders brought in from wings - whereas this should be the other way around as my placeholders in sketch-up were the same size as the pylons. Problem is you cant rescale the imported Sketch-Up 3ds once in wings as it simply disappears
or produces an error.
If it's possible to figure out a direct scale equivalent between units diplayed by wings and that of sketch-up then maybe this task is possible. More experimentation would be needed to ascertain what the relationship is to get things looking the same size. Any error would mean the placement of the pylons on the scenery would be off (maybe scaling in LE could address this?).
Note that Im using a trial version of Sketch-Up which still has the 3ds export filters operational. One still has to spin the model around the principal axes a bit to get it showing the right way up in wings. Once the trial period expires this task will become more difficult. Probably requiring importing through Blender to get what you need out.
Basically its a hassle to attempt this - just placing pylons without connecting cables makes a lot more sense!! They are still useful in the training context.