You can set the order of pages searched for the index page by doing the following:
- Login to Plesk
- Click your domain
- Click Web Directories
- Click Preferences
In the section labeled Documents, you can set the order of which files are searched. If you want index.aspx instead of index.html, you would make sure that the index.aspx is listed above index.html. If you would like a filename that does not exist in the list to be your preferred filename, you can add it using this same section.