Problem with Cache Manifest on iPad

I'm attempting to load up some of our web content into the iPad's cache for off-line access using a Cache Manifest. When configured properly, cached html pages are available when no WiFi access is available. This works perfectly on my iPhone and iMac both running Safari, but on the iPad it does not work at all. I have tried this numerous times with no luck - always works on the iPhone, never works on the iPad. I assumed that the iPad is running the same version of Safari as the iPhone, but obviously something is different. I have been able to get a few pages to be cached, but once they are cached they can not be changed or deleted. Modifications to the CACHE MANIFEST file on the server are supposed to trigger a cache refresh and it does on the iPhone but not the iPad. Going into the iPad's settings and clearing the Safari's cache does not work either - the files are all still there. Has anyone tried this with any luck?