The only way I have found around this is to put the HTML5 in an Iframe and loading them from different domains. Then they both work.
http://network.iwarecd.com/appbuilde...how/frame.html
For most people this is not good as they only have one domain to work with but here is what I did. These are both on the same root domain and I just added a different subdomain...
One is on network.iwarecd.com the other is on rtp.iwarecd.com so they are both pointing to iwarecd.com just that network and rtp are in different folders and using different application pools.
I have not played with this much so I don't know how well it work on all browsers, how long it will work once it starts, if I need different application pools or not, etc.
Hope this helps.