How can I determine the inertia tensor of a complicated part?

Hello,

I made a model in SimMechanics of a mechanical walking robot which is walking down a slope only kept in motion by potential energy. To make it walk properly I have to change the parameters of the model. For example friction in joints, weight of the parts, position of the center of gravity of the parts.

This will be built later with these aluminiu profiles: http://www.robotunits.com/contentimages/scaled155-155-PIL4040.jpg

As you can see the Profile has a Complicated structure so I can'T calculate it by hand. Are there any programs that can do that? And if so, is there a program that puts out a formula to calculate the inertia? So that I can easily change the center of grvity in my model without running the inertia determination program again.

Kind regards, Philipp