How to import a object with different materials using the same texture?

hi all I am currently working on unity 3.1 version. I have a .max file,there are two sub-objects in it, each with different materials but using the same texture.Two diffrent materials have different ambient and diffuse settings. It looks good in 3dsmax.When I imported it into Unity,only one material is used on both sub-objects.(By detecting only on texture is used?) If I let the object using 2 textures(same content diffrent file name...),it works ok but i will double the texture size.. Any way to fix this problem?Thx~

On FBXImporter there is setting "Generate material". By default it is set to "Per Texture", which means all meshes in your project will try to use share materials (based on textures). You want to change that setting to "Per Material", then it will import each material separately.