Flexible Rotation/Translation Sub-Assemblies

[gfunnybus]

I've got a torsion spring problem. I need to show a torsion spring in an iAssembly with positional reps. There are already quite a few flexible parts in the assembly. Unfortunately, geometry cannot be flexible. So, as a work around, I created two halves of the spring. I went about constraining them with a rotation-translation constraint so the spring looks like one part when the angle changes. Now I am running into another problem. When I place the spring into the assembly and enable flexibility, the rotation/translation constraint seems to fail and it moves freely. Does anyone have any insight on this? I will attach the spring.