Modal analysis for rotating systems

Hi,
I'm trying to perform a rotational dependent modal analysis (linear) in Motionview for a simplified rotor system. The task is to investigate eigenmodes associated with the blade joints at different rotor frequencies.  How do I perform multiple modal analyses with varying rotor frequency?

Or alternatively, how do I define a modal analysis with a a defined motion (e.g. 1/2 nominal rotor freq.) as previous step? Currently, the linear analysis option changes the motion to fixed, thereby eliminating the effect of motion. "Static + linear" option sound promising, but the static step is difficult to perform since the rotor needs time to speed up (just as in reality).

Any ideas? See simplified model included.

Cheers,
David