So - I created a custom model and succeded in bringing it in game as far as the geometry and skin is concerned.

I just can't figure out this problem:

I got a whole bunch of hardpoints on the model - some of them hidden in the geometry to place 'invisible' parts.
As soon as you attach a component (engine, jewelry etc.), the model vanishes completly. Only the 'attached' part remains and can't be deleted anymore. You can't attach other parts to it either.

I dunno what could have upset the system. Any clues ?