There is a discussion on Neptune, the 12th House, and Pisces by Maurice Fernandez going on over at the forum at astro.com that folks may be interested in.
Click on Neptune, the 12th House, and Pisces
Fernandez presents an interesting alternative that Neptune is related to career placement - an idea I was fascinated with. His book isn't that easy to read, but it may reward the persistent reader with a whole new way to look at Neptune. Summaries of Neptune in the various houses are included in this thread, as well as samples from my files which suggest that natal Neptunes definitely do influence career preferences.
BTW: I go by the name of "Evescaduceus" on this forum, or just plain "Eve". I love hearing from my readers (I almost always learn something from all of you), so say hello.
SOURCE: Fernandez, Maurice. Neptune, the 12th House, and Pisces, Trafford Publishing, 2006.