Not sure, but I recall somewhere I read that 3dcanvas does not export animated DirectX files.
If this is so, when you export the model you are actually deleting its joints and skinning info.
I had plenty of experimental model debugging with modelers, (gamespace, milkshape, max, carrara, fragmotion, truespace, shade, accutrans and C4D among others) and so far the most difficult part for them is to import an X file correctly (if they do at all), and hence exporting it removes many features, from normals, uv, joints, Etc.
Sadly you have to test them and ignore their promotional material.
One exception is fragmotion, which I finally kept as my main skinning and animation for X files, even though is the cheapest one. It also work great for analizing, modifying and converting models to other formats, and even does 3d paint. The author has added many of the features I asked, so am really satisfied with it as you can perceive. It has a free trial so you can test my theory about your problem.
May the 3d force B with U
