There's a Softimage HRC exporter available from the DStorm website that will get you LWO to Softimage HRC format.
As for going the other way, I think you're out of luck.
The following page gives a few details on the only tools I've seen to do this (Deep Expoloration or Polytrans), but I don't think either of them come cheap...
http://www.3dlinks.com/links.cfm?cat...bcategoryid=11