OK on Enter, not Return

FROM : James Walker
DATE : Fri Jun 06 19:54:50 2008

I have a dialog containing an NSTextField and an OK button.  I'd like
the Enter key to act as an equivalent for the OK button, but the Return
key to add a line break to the text.  What's the best way to do that?
--
  James W. Walker, Innoventive Software LLC
  <http://www.frameforge3d.com/>