About NGUI UI2DSprite change shader's param

[lbddk]

i made a cum shader for button with ui2dSprite,and i need to change shader's param value.then i found it not work.
i found that ngui use dMat instead of the normal one which we can change. so if i use ui2dSprite.material can only get just like a model not object. so , if i use ui2dSprite.material.setFloat("test",1) that this will not work.

if there is some one know about how to let ui2dSprite.material.setFloat work,please help me and give me some answer thank you .

[ArenMook]

If you need to set some value in the shader, set the UIWidget.onRender callback and do it inside.