I am not an expert in html, but should the link not end with "index.html" (or whatever you named the auto detect html file to)?
Here is the code I use for my iframe links ...
<iframe src="http://www.nautic-vr.com/projects/temp/Lagan/Flevojachtbouw.html" height="482" width="510" frameborder="0" scrolling="no"></iframe>
I also tried the 2nd link in your post and tried it with my iPad, but couldn't get it to work. I notice you ended the link with a / . If you were to supply the full url, I could test further, or if you can't do that, just take the iframe code and alter it to your requirements then FTP the file to a test directory on your web server to test.
hope this helps,
Professional user since TW 1.30 & PW 4.0 - July 2005.