Hello Marcus_Wright,
Quote: "Could You tell me is it possible to add two shaders at once on one entity?"
In FPSC, "Shaders" are called Effects, so if you want to add two or more effects on an entity or segment, I think it is impossible unless the guy, who has programmed the shader has embedded multiple effects together when programming the shader file and further important the game engine be able to use them.
In each texture however, used in an entity or segment you can use three types of shaders: Diffuse map (yourtex_D), Normal map (yourtex_N) and Specular map (yourtex_S). Please, note those maps (Diffuse, Normal and Specula) just mentioned do not demand shader programming ( .fx files) as those you can find out in Effectbank folder because they are graphical files only.
I hope this might help you to clarify your question.
Cheers,
Northern