Are you sure the "flattening" command shown in your screenshot is in the production release of NX 10? Using the 'advanced' role, that command doesn't show up anywhere for me (NX 10.0.3.5).
I saw a demo of that command (or a similar one) at a RUG event last fall and we were told it would be in NX 11.
In 10.0.3 it can be enabled, BUT, the output is a non-associative body
In NX 11 is the full on feature, it creates a feature in the feature tree, it's associative.
It also supports reforming of curves etc.
I've attached an example with several solutions - some produce flat pattern curves, others will deform the surface. They each have their own tolerances and produce different results (some use material properties), so you'll have to decide which one suits your need:
The only one which I had problems with was Global Shaping. It works until the helix goes beyond 360 degrees.