I just discovered a way to create Google Apps aliases (nicknames as Google states) without the mention of “on behalf of” when using that email alias. I even found a way to avoid the 30 alias / nickname limit on Google Apps.

First you go to Google Apps domain control panel.

• Click on “Users and groups”
• Select your main user account
• at the bottom of “Nicknames” you select “Add a nickname”
• Choose an alias (nickname) you want to use and click “Save changes” at the bottom

After this step you go to your Google Apps mailbox.

• When in your mailbox on the desktop click on “Settings” at the top right of the screen.
• Then click the tab “Accounts”
• Under “Add another email address you own” there is an extra option:
  When receiving a message:
  * Reply from the same address the message was sent to
  * Always reply from default address (currently admin@mydomain.com)
  I myself prefer the first option, then if i reply to a new email send to my alias it will automatically reply with the correct “From” alias
• Press “Add another email address you own”
• At “Email address:” type the alias / nickname you entered at your Google Apps control panel.
• At “Name:” enter the name you want to be displayed when an email is sent from this alias.
• Click “Next Step”
• This is the important step ! Choose the second option !
  “Send through mydomain.com SMTP servers (recommended for professional domains – Learn more)”
  (if you choose the first option the mails will be sent with the mention: “on behalf of” !

• Now enter in the field “SMTP Server:” smtp.gmail.com
• Select port: 465
• Now enter in the field “Username:” your main Google Apps login (same as you use to check your Google Apps mail!) example: admin@mydomain.com
• Now enter in the field “Password:” your main Google Apps password
• Then check the box: “Always use a secure connection (SSL) when sending mail
• Then press the button “Add Account”
• Now a confirmation mail is send to your main Google Apps account
• In that mail click the confirmation link or copy the confirmation code to the window and press “Verify”

Now go to your inbox, compose a new mail and then you should be able to select your new alias in the “From:” field. If you now send an email it should not mention “on behalf of”

If you have 1 main user in Google Apps control panel, Google sets a limit of 30 nicknames.

You could skip the step of making a new nickname in your Google Apps control panel.
But then be sure to turn on the “Catch-all address” in your Google Apps control panel:

• Go to Google Apps domain control panel
• Click on the tab: “Service settings” and select “Email”
• Then turn on the “Catch-all adress” and choose the second option:
  Forward the email to: “your-main-useraccount”@yourdomain.com
• Be sure to click “Save changes” on the bottom of the page

Then go straight to your inbox, settings, acccount & create a new “Send mail as” (with the smtp settings) without first creating a nickname in your Google Apps control panel.

Then after the new “Send mail as” is created (without a nickname in the control panel) you will have to send yourself an email to that alias. Only after that you’ll be able to choose that specific alias in the “From:” field when composing a new email.

I don’t think there is any limit in creating new “Send mail as” aliases in your inbox settings, so you won’t have the 30 nickname limit and you won’t have the notice “on behalf of” when using that alias with the proper SMTP settings.

I hope it’s of some help to the Google Apps users