Please add support for the Sender Rewriting Scheme (SRS) in Symantec Messaging Gateway.
https://en.wikipedia.org/wiki/Sender_Rewriting_Scheme
Whenever emails from sender domains with SPF records are forwarded, the sender needs to be rewritten. SRS is a best industry practice to ensure that
a) SPF-Checks at the recipient side don't reject the email
b) Recipients can reply to the original sender.
Symantec Messaging Gateway supports email forwarding, it should also implement SRS to ensure that a sender's SPF-records don't break forwarding.