Firstly, you need to load every IM mesh into IM Editor, switch to the Pro mode and change the material type to the tbumptex. Then, to get specular, you have to set specular color (recommended value is 150), where black is 0 (matte) and white is 255 (shiny).
Then you need to get normal map and specular map. Use every normal map editor to create it. Find the best result by experimenting. (mine result isn't perfect at all cause it was fast conversion). When you got the normal map, you need to get specular map and put it in the alpha channel of the normal map. Specular map works as specular filter and each pixel of this map gives certain specular value to the model. White color - totally shiny, black color - totally matte. Usually i take the diffuse map's green or blue channel and adjust it.
If you got the specular map, put it in the alpha channel of the normal map and save as 32-bit TGA file. Create a texture.txt file for it and don't forget to write "Alpha=<your texture name>" string - this will engage specular map in the game.
If texture.txt file is ready, you need to pick a Normal map in the IM Editor. Pick the texture.txt file you just created and save.
Repeat this with all meshes that need material conversion.In