On a recent Citrix Access Gateway implementation, I found these links to be very useful and thought I’d pass them on:
Access Gateway Administrators Guide
http://support.citrix.com/article/CTX117022
Citrix Access Gateway Port Configuration
http://support.citrix.com/article/CTX113250
Convert PFX Certificate to PEM Format for Use with Citrix Access Gateway
http://support.citrix.com/article/CTX106028
How to Forward Credentials from Access Gateway to the Web Interface