I have been trying to migrate a site from a plain vanilla IIS 5 box and have had no luck importing the key into the Plesk Interface, unfortunately I am left with only the key I export from the original server. The message I get is:

Unable to set the Private Key: Probably, the private key format is invalid.

I have tried every method of exporting the key and importing. The key imports fine into IIS 6, but not the interface.

 

Try This

Check this page out:

http://www.petefreitag.com/item/16.cfm

It helped me when I moved from pure IIS to plesk..

Russ