MAIL archive on external Drive

Hello!

In order to win some storage place on the harddrive of my MacBook Pro, I’d like to archive the E-Mail older than 2012-01-01 somewhere on my external drive.

I already gathered some information on this topic, but it’s still not clear how I can identificate the actual location of the archive on my computer harddrive.

The idea would be to move the archive location from ~/User/somewhere over to ~/external_drive. But I don’t see yet how MAIL is supposed to understand that an E-Mail is stored outside instead of just locally. It seems there is an option for local storage, when creating a new Mailbox, but I’m still looking for a kind of “remote storage”.

My archive on the external drive should look like this at the end:

…

2010_Q4_Archive

2011_Q1_Archive

2011_Q2_Archive

2011_Q3_Archive

2011_Q4_Archive
…so I can add new archives as time goes by.

If my external volume is connected, I’d have the E-Mails appearing in MAIL.
If the external volume is not connected, I’d not access them.

Any hints would be much appreciated.

🙂

Important: I’m not interested in using time-machine! I look for a pure “external volume fix”.