GW 8 hp2
NW 6.5 sp8

I have tried it checked in C1.
I currently have /flatfwd in the gwia config file.
I have restarted GWIA after each change above.
I have NOTHING in the FROM field in the rule.
I have NOTHING in the body text of the rule. NOTHING anywhere except in the TO field.

This happens with external emails sent to GrpWse & fwd'd off to an external gmail. When a message gets forwarded, it is still tagged as FROM: my GrpWise email account.
I've tried a number of variations in the format of the forwarding address:

ourdom.GWIA:<gmail address>
OURDOM.GWIA:<gmail address> - checking case sensitivity (listed as lower case in C1)
GWIA:<gmail address>
<gmail address>

All 4 work exactly the same.
When I hit 'reply' from gmail, it goes to my gmail, not the email of the sender.

What else can I review/modify to achieve the results of /flatfwd as it was designed??