How to visualize a Composite Material from 3d Max

Hey there,

This is probably going to be a very stupid question but I’m a complete beginner at building materials in UDK.
So basically I’ve got a Composite material in 3d max. It’s composed by a basic diffuse texture of a wall, and a decal that contains an alpha and damages to the wall (stains, cracks, and that sort of stuff).
The base texture (wall) is in UV channel 1 in Max. The decals are in UV channel 2, so they pretty much show only in certain places. Right now what I managed to create in Unreal was a material where both textures are on top of each other (thanks to the “Add” node), but both are using the same UVchannel and the alpha mask to cut the decals doesn’t show properly, so they look as blended on top of the base texture.
How can I set up that kind of composite in Unreal?
Thanks a lot!