As an owner of X10, I can confirm that it is exactly the same as importing media into X9.
Just grab a copy of Entity Workshop by Wehtam or Doomsters Model Maker.
Make sure that you have the correct path set up to export the media to, otherwise, you will get errors.
I am still amazed that people are finding copies of X10! I keep seeing new people flashing up in the forums asking questions about it.
I'm not accusing anyone of piracy, as you might of purchased it a while ago and have not been active in the forums, but, there seems to have been an influx of new members asking about X10.
Unfamillia
EDIT - in regards to mods, check out Mystic Mod. Its designed for X10 and adds a fair amount of stability and scripting add ons.