Can you use COLLADA to go from one to the other? (.DAE extension)
I know that, in the past, the free versions of various content creation tools have purposefully been crippled, so that you can't use them with the higher-cost tools, to avoid studios buying one or two copies of the expensive tool, and then using the free tool for most of the work...
Jon Watte, Direct3D MVP
kW X-port 3ds Max .X exporter
kW Animation source code