Here are a couple tips on textures:
The Valve material compiler (vtex.exe) will not create directories in your game’s material folders. So if you have a Material Folder Path for the model as myName/myMap/stuff … then there needs to be a folder that matches that before trying to export the textures in C:…game/materials/myName/myMap/stuff (inside stuff will be myMat1.vmt/myMat1.vtf, myMat2.vmt/myMat2.vtf, etc). This is the most common missing step by users learning the ins-and-outs of the tool.
The tool can only export TGA bitmaps.
At the moment, the only materials that can be on your model to always work are Standard and Multi/Sub-Object. In the docs it mentions Shell (since RTT makes a shell material) but shell isn’t yet supported by the SMD Exporter… so after you do RTT you need to get the baked material and apply that to your model.
Here is a fuller run-down of materials:
Basic Texture Overview
Detailed Explanation of Material Exporting
Here is a map of what material maps will get exported from 3ds to Source via the texture exporter:
And here is a video overview on exporting textures:
Hopefully that helps getting the textures to work
Hearing things like that always encourages me.