I had the same problem like all beginers with irrlicht ... how to create big mesh with more than 1 texture...
I found a plug-in for 3ds max 4 and 6 that exports the mesh in .3ds format but with texture
For those who didn't understand what I sayed have a look here
After exporting the mesh in gothic.3ds format u just need to put the textures used for the mesh in the same folder with the mesh
Hope it helps someone...