Kerbal Space Program

I've created a relay satellite. But one around the moon is too few. So I put two in the protective shell. But why should I fly twice? So I made a subassembly from the shell with satellites (to use them later) and tried to attach the subassembly a the lower end of the fuel tank - inverted. When I started to rotate the subassembly, ends of struts and fuel lines went off the shell. When I move the shell's base those protruded ends move too but by different distance. That's weird.

Of course, this time I can change the root, copy the shell wit satellites using Alt button, rotate it and attach at the bottom (I had yet to recreate the shell which disappeared). I cannot do that using a subassembly which implementation seems invalid.

I attach a screenshot, the subassembly and a ship's stub to illustrate the problem.