Originally Posted by p3ppit
But when I open my browser (FFox), enter the url of our Citrix server, I get an error message saying something like "You have chosen not to trust [...], the issuer of this servers SSL certificate..."
This means that whoever manages the Citrix server did
not use one of the common Certificate Authorities. My
guess is that they made a self-generated certificate.
In any event, the administrator of the Citrix server
should be able to give you a certificate to import
which will add the CA to your list of trusted sources.