ENDIAN Firewall - SMTP proxy behavior and emails.

Hi there.

So, I've been using EFW Community a while now.
But I have some doubts about SMTP proxy.

My MX servers are out of my network (on Cloud).
I'm using Active SMTP Proxy on RED Zone and Transparent SMTP Proxy on GREEN Zone, with some bypassed IP addresses.
So, to use the Endian notifications, I enabled Smarthost for Delivery and Smarthost authentication.
Still on Advanced Tab, I kept marked "Require SMTP HELO" and "Reject invalid hostname".
"SMTP HELO name" and "Always BBC to address" are blank.
"Mail template language" is English, "Recipient address verification" is marked, "Hard Error Limit" is set to 10 hard errors, "Maximum email content size" is set to 30MB (as require by my MX server provider).
"Enable DSN on zones" is set to GREEN and RED.
All options below "Spam prevention" are marked.

Initially, i received "Sender address rejected" when trying to send emails through the proxy.
So, I added the GREEN network scope to the "Whitelist Client" field on "Accepted mail (Black- & Whitelists)" inside "Black - & Whitelists" tab.
Tested the functionality of the SMTP with success. Everything worked just fine.
Then, I added my FQDN to the "Whitelist Sender" and "Whitelist Recipient" fields on "Accepted mail (Black- & Whitelists)", "Spam greylistling (Whitelists)" and "Spam (Black- & Whitelists)" inside "Black - & Whitelists" tab.
Still, everything is OK.

But I noticed somethings that I'm concerned about.
When the email arrives to the destination, it comes with the correct sender address, but on the MX log, it shows the Smarthost username.
Also, when any e-mail stays stuck on the mail queue of the proxy (manly with domain not found error), neither I, the sender or the email used as smarthost username receives any notification.

Are my settings right? Is that the way that is meant to be configured?
Is there any tweak I should do?

Best regards.