Setting Default Preferences in Mozilla on OS X

I am having difficulty changing the default preferences for Mozilla
1.4 on Mac OS X (10.2.6). I following the steps in the last section of
a reasonably clear guide found at

http://www.mozilla.org/catalog/end-user/customizing/briefprefs.html

However, no default preferences were changed. 
Below is what I have done.
1.  I downloaded a fresh copy of Mozilla 10.4
2.  I opened Mozilla, customizing the preferences.
3.  I quit Mozilla.
4.  I copied ~/Library/Mozilla/profiles/default/******.slt/prefs.js 
      to the desktop for easy access.
     (A quick check with a text editor of this file verifies that it
      does indeed contain the customized preference settings.)
5.  I ctrl-clicked on /Applications/Mozilla and clicked 
     "Show Contents"
6.  I copied prefs.js to 
     /Applications/Mozilla/contents/MacOS/defaults/profile/user.js
7.  To emmulate a clean install, I trashed /Library/Mozilla and 
     ~/Library/Mozilla.
8.  I started Mozilla. There was no change in the default preferences.

SECOND ATTEMPT
9.  Repeat steps 1-5
10. I appended the contents of prefs.js to the end of 
        /Applications/Mozilla/contents/MacOS/defaults/pref/all.js
11.  Repeat step 7-8
12.  No change in the default preferences.

Any help would be greatly appreciated!