Rusty Muffler

[dadi_oh]

I have a 2006 Yaris RS hatchback that went into service Nov 11, 2005. After a couple of winters on Ontarios salt covered roads the rear hanger for the exhaust has started to rust and has spread onto the rear surface of the muffler itself. What I was thinking of doing was to spray the rear of the muffler (or possibly the whole underside of it as well) with flat black manifold paint. I thought this also might be a visual improvement since I think the focus should be the tail pipe and not the silver (aluminum) rear of the muffler anyways.

Anyone ever try this? Would the paint adhere properly? Would I negate any kind of factory muffler warranty by doing this? For that matter should this be covered under warranty or would it only cover a large hole eating through the muffler.

Thanks