IE 8 does not support HTML5, you can use IE 9 (and IE 10, prerelease too)for the same.
Read this article around this.
I am having the same (more or less) issue. I don't understand why the index.html (html not html5) doesn't just deliver the shockwave .htm and .swf when the broswer/device doesn't support html5.
It looks to me like the index.html using browsersniff.js should do that.
We need to add iPad to our delivery but our primary online product (that we write training for) doesn't yet support IE9. We can't ask our clients to update their browser intil the product supports it.