Specularity forms

Hello guys,
Im wondering if i can make my specular with a diferent form, because for every material i put the specular effect, its like a ‘white spot’, and sometimes i want simulate a window effect, like a specular of an eye for exemple. I tried to put some textures on lamps too, but in this case the form of texture affect the entire material, not only the spec. Tried to push ‘no diffuse’ button to see if affects the spec light, but not work. The effect i want is something like this:http://www.luxrender.net/wiki/images/9/9e/Spec_color.jpg with give me another shape of specularity, diferent this wich is the most comon effect:http://www.directxtutorial.com/Graphics/Tutorial9/Direct3DBasics/dx9B3-19.PNG

I appreciate the help. Thanks.