This problem can be resolved in a very elegant way using a .htacess file. The content of the .htaccess file should be:
Redirect 302 /index.html http://your_asp_site.com/Default.aspx
If you want to change the directory index in the future so it loads “Test.aspx” for example, you should just replace the “Default.aspx” string with “Test.aspx” in the .htaccess file.