Hey, Steffan,

Don't know if you've solved this by now but I just thought I'd reply. You can map sub-d's on a face level in standard (heirarchy) mode. Right Cliick on the object and pick standard (v. 4.0 or 4.5, heirarchy 3.0), then RMB again and pick faces. Select the faces you want then Middle mouse drag the material from the hypershade on to it as usual. The thing is if you do it in Polygon mode, the polygon proxy object will get the material, not the Subdivision object.