I found some great advice on this subject that could help you out with your question: https://www.msconnection.org/Discussions/f31/t44089/Voluntary-Self-Identification-of-Disability-(Fe

The main points seem to be that you should limit how much you self-identify. Usually employers will ask for this information to meet federal guidelines (if they have contracts with the government). Talk to your HR department or local EEO office if you still have any questions.