Material instance setup PBR Packed Metal Rough AO

Hi there,

At the moment i’m trying to setup a material to use as a instance for a lot of objects that are using a Color texture and a texture with Metal Roughness & AO properties, these are combined in to one texture for optimization.
Al texture slots should be parameters so i can create instances of this base material. Normally without making a parameter texureSampel the combined Metal Roughness & AO texture work fine. Now that a have set it up as an parameter texureSampel for a material instance, this doesn’t work anymore. (don’t see any roughness) Is there an workflow that makes it possible to use a packed Metal Roughness & AO texture as a parameter for an instance.

greenChannel: Roughness
blueChannel: matellic

Thank you!