Its hard to take pictures of a black thing, especially when you have crappy lighting, but its deliciously primed now:
Some tips for removing underseal:
A scraper is your friend for the flat areas, I used several wood chisels.
A wire brush on a grinder smears the stuff around at first, but will take the bulk of it off.
The 3M strip-discs are terrible at full strength underseal, they smear it around and then get clogged. They are excellent at cleaning the steel up after you have wirebrushed it to get it ready to paint.
Once you have most of the underseal off you can get the last bits off, and the film the wirebrush and the grinder leaves with wax + grease remover or thinners.
You can put underbody sealer straight onto bare metal, but thats a bit old school. When it chips you can get accelerated rust as it holds the moisture, and if any petrol or anything gets on it, it washes off and leaves bare metal.
Better way is to prime with a good quality 2-part epoxy primer, as these are waterproof, and then blast with either stone-chip guard or underseal to protect from rocks possums etc.
Also are those pictures above massive for everyone else? I can't seem to resize them on photobucket.