Hi there! :)
I'm developing my shaders using FX Composer 2.5 ... i did different light models like Lambert, Phong, Blinn, Ashikhmin-Shirley, Cook-Torrance, Oren-Nayar, Ward and Kajiya-Kay. The shaders are compiling and working fine using FX Composer, but in XNA just Lambert, Phong and Blinn are working - all other lighting models are ...