interesting, so is it possible to customize it to be the same format as it is sent from zen cart? and customers won't realize it's from stamps.com?
If so, could you share how to do it?
Never mind, I figured it out, however, it's still not good enough.
This is just a FYI for anyone who may have had a similar problem.
I have everything working, but I had to change order status 3 from DELIVERED to SHIPPED in ShippingZSettings.php and ShippingZZencart.php, as zencart's default order status 3 is SHIPPED, not DELIVERED.