Sonia,
If you look through the communities you will find 3 videos around SSL Overview.
Gateway Training-Session2_PT1-SSL Overview-Inbound-20141125.mp4
Gateway Training-Session2_PT2-SSL Overview-Outbound-20141125.mp4
Gateway Training-Session2_PT3-SSL Overview-CRL_OCSP-20141125.mp4
Also we have attached a working document on some of the pieces of the Certificate management within the gateway.
Sincerely,
Stephen Hughes
Director, CA Support