Attached is the Sec. Navy Instruction 1850.4E, Navy Disability Evaluation Manual. This covers PEBs. Chapter 8 contains the standards of fitness for retention (i.e., what conditions require referral to MEB).
I just found this manual while researching for someone online. In this manual is a list of analogous codes the Navy uses to rate disabilities that aren't in the VASRD--yet. This could really help someone whose code isn't listed to find out at least what the Navy standard is and what an approximate rating would be.
There is also a similar Table of Analogous Codes (TAC) in the since rescinded DoDI 1332.39. I do use both as a reference and starting point for an analysis of potential likely appropriate ratings (another resource you can use is searching Board for Veterans Appeals decisions for rare/unlisted conditions and see what the VA used to rate these conditions). The only point I would add, though, is that when using an analogous code, there may be more than one way (and more than one applicable appropriate analogous code) to rate a condition...in these cases, the member should be rated at the higher of the two ratings under either criteria. The point is that this can be a complex issue, so I would definitely say it makes sense to reference the TACs, just keep in mind that these tables are not binding. If you deserve more under another proper code, that is what you should receive.