Decal with metallic channel?

Hello, everybody. I have some problems working with decals. I need to use decal with metallic channel. But, using DBuffer mode is not available, because DBuffer is not supports metallic channel. Translucent mode did not worked as well, because it adds translucency to all the decall, even when translucent mask is 100% opaque. Can you help me with advice how to use decals with metallic and working translucency channel?