I am not sure what you are saying - which ring wasn't on the system map? And what it has to do with my picture? Are you saying that your ring from the above post is the same as mine (mine is around a gas giant and yours looks like around a brown dwarf)? It looks much denser (it's almost as dense as parts of the "internal ring" there). Look how faint mine is (in comparison to the "internal ring") and it's the most massive planetar ring reported (it's HR 5397 A 8 B Ring from
this post and it obviously was visible on the system map as I had it pictured there). If it's the same then it seems like they've changed how it looks - perhaps they've tried to make such rings more visible, generally.
Anyway, my point is that with faint enourmous rings you shouldn't have the Galaxy disk in the background because you will probably not see them, then. Your OP ring is over 3x larger and has only 2x as much mass so I think that with similar lightning it should be much fainter but still visible - it's difficult to compare, though, how much light it gets (and reflects - such rings are too diffuse to absorb enough light as to make their backgound visually fainter) so perhaps it really can't be seen.