Add X-Forwarded-For to Email Header

Hi,

I managed to forward client IP using X-Forwarded-For HTTP header from Citrix NetScaler LB to Exchange.

Is there a way for Exchange MBX+CAS to take this info and add it to the message header? I found ways to add it to IIS log. But that's not sufficient to trace back the message to the source client IP.

I'm running Exchange 2013 on Windows Server 2012 R2 (IIS 8.5). The X-Originating-IP is showing the LB IP.

TIA.