Need Help decrypt HTML E-mail using OutlookPrivacyPlugin

[David J]

Hi,

I've installed dejavusecurity/OutlookPrivacyPlugin to decrypt e-mails from
outlook.

It works well with encrypted text email but under features its says it can
decrypt HTML e-mail.

I'm collecting data from an online form and I want to send the email as a
form with the data filled in.

I encrypt the HTML form using gpg then send as an e-mail.

When the email arrives in Outlook it decrypts but displays at the top:

** Message decrypted. Message was unsigned.

then the HTML code.

Is there any specific way I need to prepare the HTML email then upon
decryption it appears as an HTML email ready for printing.

Any clue as to how I get this to work is welcome.

Thank-you in advance!

David j.