Thanks for the infos Diane.
I find a solution.
I create a folder in the Entourage sounds folder called "sound_1.eradgesoundset", i call it sound_1 but it can be what you want. The important thing is the .eradgesounset.
I put in this folder my sounds, for exemple :
welcome.wav
soundset.plist
No Mail.aiff
reminder.wav
New Mail.aiff
Mail Sent.aiff
Mail Fetch Error.aiff
goodbye.wav
You can put in what you want, mp3, aiff or wav.
Then i created a file with BBedit call :
"soundset.plist"
This file must be in the "sound_1.eradgesoundset" folder with yout own sounds.
This file look like this :
--------------------------------------------
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
"
http://www.apple.com/DTDs/PropertyList-1.0.dtd <
http://www.apple.com/DTDs/PropertyList-1.0.dtd>">
<plist version="1.0">
<dict>
<key>SoundSetFileFormatVersion</key>
<integer>0</integer>
<key>SoundSetUserString</key>
<string>My soundset</string>
<key>SoundSetURL</key>
<string>
http://www.officeformac.com</string> <
http://www.officeformac.com</string>>;
<key>SoundFile_MailError</key>
<string>Mail Fetch Error.aiff</string>
<key>SoundFile_MailSent</key>
<string>Mail Sent.aiff</string>
<key>SoundFile_NewMail</key>
<string>New Mail.aiff</string>
<key>SoundFile_NoMail</key>
<string>No Mail.aiff</string>
<key>SoundFile_Reminder</key>
<string>reminder.wav</string>
<key>SoundFile_Welcome</key>
<string>welcome.wav</string>
</dict>
</plist>
------------------------------------
the "<string>
http://www.officeformac.com</string> <
http://www.officeformac.com</string>>;"
you can put what you want here between the open strings.
the <string>My soundset</string>, can be what u want to and also nothing.
Then Open Entourage and select your new soundset in the menu.
Hope this help
I cannot inderstand why MBU do not make a simple solution to select other sounds !