Programmatically stop FireFox from storing content in memory cache?

In my web application, I send all the usual response headers to the browser to prevent caching (Cache-Control: no-store, no-cache). Content expiration is also turned on.

However, if I log out of my application in Firefox 3.6 and then navigate to "about:cache", I can see HTML content from inside my application in the memory cache. I've also tried a couple banking/credit card sites and saw the same issue.

Is there a way to prevent Firefox from caching content not only on disk but in memory so that someone else can't come along and examine the memory cache later? I can always ask my users to close the browser after logging out by there's no way to guarantee that they will.

Response headers and meta tags (there's several that say not to cache) are treated more like suggestions than rules. That's why most bank websites tell you to close your browser after you log out. So to answer your question directly: No, there's no way to guarantee that a browser will listen to your suggestions about what to do with the data you're sending it. Same this is true for the look of the site.