How to change default CD burner for iTunes?

Alright, for christmas I got an external CD burner. I am trying to back up my entire library to discs.



The problem is, when I click ';Back Up';, my built in, old, non-working, CD burner ejects for me to place a disc in.



How do I change it so that when i want to back up discs it chooses the new external burner by default?How to change default CD burner for iTunes?
Check the site bellow which explains how to change the cd burner



http://forums.macnn.com/90/mac-os-x/1951