A few actions to manipulate the new Substance materials in Unity 3.4.
Use Get Material to get the Substance material. Currently you have to check Get Shared Material, which means all instances of this material will be effected. Apparently this limitation will be removed in Unity 3.5.
Use Rebuild Textures after setting Substance properties.
Still working on other Substance actions, but these actions should cover a lot of common use cases...