Upgrade Plesk 9 trial license to Plesk 10 purchased license

Had to do an upgrade of a server that had Plesk 9 with a trial key (single domain). It wont let you upgrade to Plesk 10 without a key upgrade and you cant use the Upload Key on the main license page since its a key for a newer version.

So what to do?

After going around in circles for a few minutes I realized all you need to do is select the tab that says additional license keys and use the upload key option on that page. Problem solved!

I could then proceed to upgrade to Plesk 10.