Any hard documentation for x-forwarded-for?

Dev,

I was tasked with setting up a VS for a client and passing https traffic through the load balancer. I found the correct settings to get that working, but I'm also SNAT'ing the traffic. The client want to be able to do x-forwarded-for to get the true client IP address. I think I understand the reason why the x-forwarded-for won't work on https, but I need something hard fast from F5 saying this is why this won't work. I'm still very new at the LTM's, about six months in, and I don't really get the benefit of the doubt just yet when it comes to these sorts of things. Has anybody successfully sent an x-forwarded-for WITHOUT SSL offload at the LTM? If so, what were the steps? Also, if anybody has any docs on the headers, that would be great.

Thanks,

John