Hi!
afaik CAF stands for coded audio file. Just convert an mp3 or wav to aiff using Quicktime (pro for Windows) an then rename the ending to caf. That'll do.
However, I am still looking for a program to adapt the plist and strings files in Win XP. Up to now, I tried Notepad, Notepad2, eclipse Java Development Kit, jEdit, Word and a hex editor but none worked.
Do I have to recompile the file after having changed it? Or is this just plain text changing?
EDIT: ok, it's easy: Use the strings to XML decode which can be found here somewhere

(here:
http://140.124.181.188/~khchung/cgi-bin/plutil.cgi)
Then use jEdit (download from sourceforge) to edit the new XML file.
In sounds.plist you can change the following part:
<key>validTitles</key>
<array>
<string>NONE</string>
<string>DEFAULT</string>
<string>ALTERNATE_1</string>
<string>ALTERNATE_2</string>
<string>ALTERNATE_3</string>
<string>ALTERNATE_4</string>
<string>ALTERNATE_5</string>
<string>ALTERNATE_6</string>
</array>
<key>validValues</key>
<array>
<integer>0</integer>
<integer>1</integer>
<integer>2</integer>
<integer>3</integer>
<integer>4</integer>
<integer>6</integer>
<integer>7</integer>
</array>
</dict>
You can add a line <string>ALTERNATE_7</string> here and also <integer>8</integer> a little below.
In the file sounds.strings you can edit the following part:
<key>ALTERNATE_5</key>
<string>James Bond</string>
<key>ALTERNATE_6</key>
<string>Test</string>
As you can see, I added a "Test" string which is also shown in the "New Text Message" Sound menu.
The only thing which does *not* work up to now, is adding a new caf sound file (being named sms-received7.caf) so that it will also be played when clicking on "Test".
If anyone happens to know a solution....I am waiting for it.
Cheers
Marc