If you don't want to have to load the texture mapp and set the colours manually, you can use the free utility Mat Pose Edit to make a MAT Pose file. To make a thumbnail for a MAT Pose in Poser 4 I compose a scene in Poser, save a pose with the name "Z" (for example). Then in Windowes Explorer I delete "Z.pz2" and rename "Z.rsr" to "MyMATpose.rsr", where MyMATpose is the name of your MAT file.