TouchKit Cache Manifest setting not working

I need to prevent any application caching by the browser in my TouchKit application.
Here’s some code that I thought would do the trick:

public class MyServlet extends TouchKitServlet {
protected void servletInitialized() throws ServletException {
TouchKitSettings s = getTouchKitSettings();

However, this does not seem to work. If I look at on the Safari debugger either on a Mac or iPhone, I see an Application Cache called safari.manifest that is signficant in size. I’ve tried to use the annotations @CacheManifestEnabled(value=false) and @OfflineModeEnabled(value=false) also with the same result. The only way that I can prevent the browser from storing this cache information is by putting it into Private browsing mode, which is a hard sell for my users.

Is this a bug or am I doing something wrong?