I don't know, however, I'm guessing it loads it straight into the vid card (or something) so you've got the dx limit going on there... If this is the case you'd need to load the file into a bank and build the mesh from the data in that. Break it up into chunks that won't exceed the limits... if you catch my drift?!
As a footnote to this... Rather you than me!! :)
As a footnote to this... Rather you than me!! :)