Sending emails from outlook using aliases

Question

So I have a personal email account [e-mail]
This email is a catch all address for the domain, setup on a Linux server using postfix/dovecot (IMAP/SMTP). I never share the email directly with anyone, and different people have different aliases. Under Thunderbird, this works great, I can choose any custom "FROM" address, postfix will never complain that this FROM address is different from the authenticated smtp address, and no trace of the real address is present anywhere in the headers.
Outlook on the other hand.. Just can't get its head around the concept, and I don't see how I can do that.
When I send an email from "[e-mail]" using outlook, the email will contain a "sender:" header which is "[e-mail]", completely defeating the purpose. A simple header_checks in Postfix removed this "sender:" header, but there is also the first "MAIL FROM:" command which is personal and not the alias.

So my question is one of two.

1) Can I get Outlook to understand I really really want only the alias to show up and for all intents and purposes show up as if it's a real email (Just like Thunderbird handles it)?
I don't mind any level of Outlook hacking, and if I have to dabble with some VB to do it, I won't mind, just point me to some resources of how I can on-the-fly modify an email being sent.

2) Can I do it in Postfix? I tried this in header_checks:

/^Sender:/        IGNORE
/^MAIL\ FROM:\ <[e-mail]>/ REPLACE MAIL FROM: <[e-mail]>

The first line successfully removes the Sender header (Which has the horrible effect of displaying "From XX on behalf of YY"), but the second one is not catching the other instances of personal appearing in headers, namely "MAIL FROM:" which is then translated to "Return Path".

Any pointers appreciated.

Answer 1

1. Create a second email account in Outlook using the alternate From address.
2. Use 127.0.0.1 for the incoming server so Outlook cannot successfully download email for the account (should this be possible).
3. Specify a valid outbound server. Enter alternate credentials to be used to send mail if the alternate account can't be used to authenticate with the outbound server.
4. Remove the alternate account from Outlook's scheduled and manual send & receive groups. This prevents unwanted errors when Outlook downloads new mail.

Now when composing new messages, change the From: drop-down to the alternate account to send messages from this address.