To correctly import the root certificate for Lyttonnet into Internet Explorer,  open IE and go to
http://www.lyttonnet.com/ca.crt

You will be prompted with a screen similar to the one below
Click on the "Open" button

You will be given information about the certificate,
click on "Install Certificate"




Click "Next"



Select the button to "Place all Certificates..." and click "Browse"



Here you are prompted to select where to import the Lyttonnet Certificate
Select the "Trusted Root Certificate Authorities" folder and click "OK"




Click "Next"



You are Finished importing now, click "Finish"



You will see a security pop-up, click "Yes"




Now to make sure the certificate is enabled for email,  go to Internet options by clicking on "tools" in Internet Explorer"
Select the "Content" tab and click the "Certificates" button.

Scroll down to Lyttonnet Certificate and select it, then click "advanced"



In the advanced options dialog, make sure the "Secure Email" is selected.




You are finished now, Hit "OK" and close the menues, restart IE and Outlook.