Setting the From Address for Reply in Mail

Question

I am having trouble setting the default “From” address for replies in Mail. When I click on “Reply” the new window opens with a default mail address I do not wish to use. This can be changes by going into the drop down box and setting a different one. This is time consuming and it is easy to send from an inappropriate address.
“Help” menu says that the default address ( top one in the drop down box) can be changed and gives these instructions:
Set the From address
Your messages are sent from the account of the currently selected mailbox. If you have multiple email accounts, you can specify a different account to use for sending all messages, or select an account just for the message you’re writing.
To specify the account to use for sending all messages, choose Mail > Preferences, click Composing, and then choose an account from the “Send new messages from” pop-up menu.
To specify an account just for the message you’re writing, click the From pop-up menu, and then choose an email address.
To change the order in which addresses are listed in the pop-up menu, reorder the addresses in the “Email address” field in the Account Information pane of Mail account preferences.
When I open the Mail Account Preferences and go to Account Information there is no list of addresses in the “Email address” just the one for the particular account highlighted in the left column eg. “[email protected]” or “[email protected]” .
I tried to move the order of the accounts in the left hand box but nothing wants to move. Clicking and holding to push one account over another seems not to work.
Anyone got any ideas on how to fix this?
NB: This is about "Reply". Default for "New Message" is setting fine.

Answer 1

i found out how to do this finally!
1) set up google gmail account to forward your emails to (from the [email protected])
2) go to your gmail account
3) go to settings (cog in right hand corner)
4) go to 'accounts and import'
5) go to 'send mail as'
6) click 'Add another email address you own' - add your [email protected] address
7) google will send a verification email with code to that email address.
8) enter code
9) go back to gmail account  >'send mail as' and select 'make default'
10) close mac 'mail' program and reopen it.
as long as you have gmail account selected as the primary account in MAIL - mail will now come throught as being sent from that  [email protected] address!!