Not everyone knows it, but the ability to import 3ds files, which was removed in XSI 7.01, came back in Crosswalk 2012.
Just click File > Import > Import FBX, and then click 3D Studio 3DS (*.3ds) in the File Types list.
For example, you could download a 3ds model of an astronaut from the NASA 3d Models page, and import it into Softimage.
eX-SI 
BTW, this is also a way to import OBJ files which crash the default OBJ importer of Softimage! 😉
Yes indeed, that is true too 🙂