CATIA imported file can't be animated by parts

[Anonymous]

Hi. Imported this CATIA assembly, added materials to specific parts, all seems ok. But when trying to rotate specific parts, the all assembly is selected/rotated. I tried click, doubleclick, right clik + unlink/+isolate, create bodyobject, create dummy object...but nothing worked out. I edited assembly in catia, file is correct there. Import is correct too. It's just a simple (but vital) thing which does not work in 3dS, I cannot select specific parts.

Any help? I'm sure something is wrong in my approach, but don't know what and I find no specific info in forums/help guide.