multiply blend

multiply blend
0.0 0


how can i do multiply blend like photoshop multiply blend??
i try SetBlendFunc() with src = GL_DST_COLOR and dst = GL_ONE_MINUS_SRC_ALPHA it is work fine but what i need to do is to make blend effected by opacity i mean when obacity is 0 no blend and when opacity is 255 full blend how can i do that on CCLayerColor?