Installing Certificate on Exchange 2010 "Private Key Missing"

Hi Patches,
I tried to import the .pfx file in the Exchange 2010 GUI. Now the GUI requires a password.
I didn't specify a password anywhere in letsencrypt.exe so I don't know what it might be?
I'm guessing it is blank but the gui won't accept a blank password.

I found an article here with guy having similar problems.

Do you think I need to jump through those hoops as well or can I generate a new certificate with letsencrypt.exe and include a password?

David