Installing your Certificate with Website Pro 3.x
You will be receiving the following four files from comodo:Root AddTrustExternalCARoot.crt
Intermediate CA UTNAddTrustServerCA.crt
Intermediate CA PositiveSSLCA.crt
domain/site certificate yourdomainname.crt
Or You can download the Positive ssl Root and Intermediate files from here.
- Add the AddTrustExternalCARoot.crt certificate as Trusted Roots:

- Then attach each certificate in turn to your websites Key Pair in the following order. At this point your Key Pair will be black.:
Yourdomain.crt
PositiveSSLCA.crt
UTNAddTrustServerCA.crt
AddTrustExternalCARoot.crt

- Your Key Pair will now turn green.
- Stop and Start the server, your site can now be found using the https entry