External SSL in Proxmox

Hello,
How can i install external SSL certificates such from Comodo into Proxmox? I found this Proxmox wiki http://pve.proxmox.com/wiki/HTTPSCer...eConfiguration but it talked about 3 files needed. I only have 2 which i got from Comodo ca.crt and bundle.crt. There is no PEM for me.
Can this comodo certificate be installed on Proxmox ?
Thanks!