Well, you could keep the insulin in a bag or something, right? Inject inside a stall?

My advice still stands. Google up the ADA and read it. It's there to protect the rights of people with disabilities, not the sensibilities of people who are easily offended by people with disabilities. There are probably people you can call with your questions.

I just googled "american disabilities act insulin" and found this: http://www.eeoc.gov/facts/diabetes.html

I'd suggest printing it out and taking it to work with you.

You can always get an insulated lunch pail and some of that portable ice stuff, right? Not ideal, but until you work things out at work...