Can I use the Raco low voltage partition with a flat mud ring?  Looking at their catalog, it says it's only compatible with the raised rings.  But it looks like the flat type has a slot in the middle for it?
http://www.hubbellonline.com/wiring/raco_bell/pdf/a30.pdf
	
		
			
		
		
	
				
			http://www.hubbellonline.com/wiring/raco_bell/pdf/a30.pdf
				