If memory serves, they should appear under the heading "Sol".
BTW, every other system is implemented in the same way.
There is a way to add individual systems (the toplevel onces anyway) to NanoFXv2Beta.
You need to add them to, if memory serves (again), in scripts/Custom/Autoload/LoadNanoFXv2Beta.py If you look in there, you will see a section adding the Vesuvius system (among others). I wouldn't really recommend adding all systems (especially not distributing the resulting file! See previous post). There are more dynamic ways (mine and JWattsjr versions) but they, so far, had a big cost, namely loading every system in memory currently added. You don't really want to do that. It will take more work to properly do this, and I currently don't really have the time for that yet.