My 4300b have only Navigate, Settings and Bluetooth buttons.
I modify IGOPATH.TXT file located in \FlashDisk folder on 4300b :
=============================================
[modules]
Bluetooth = "icons/bluetooth.bmp", "\\windows\\bluemain.exe"
Settings = "icons/settings.bmp", "settings", 1
Multimedia = "icons/media.bmp", "Multimedia", 0
Navigate = "", "\\Flash Disk\\igo\\igopna.exe"
[Multimedia]
Picture= "icons/picture.bmp", "\\windows\\PhotoViewer.exe"
Movie= "icons/movie.bmp", "\\windows\\player.exe"
Music= "icons/player.bmp", "\\windows\\xplayer.exe"
Explorer = "icons/files.bmp", "\\Windows\\explorer.exe"
==========================================
and now I have a Multimedia Button.
Verify to have PhotoViewer, XPlayer, Player exe in \Windows folder.
I use info from
http://www.gpspassion.com/forumsen/topic.asp?TOPIC_ID=110237&whichpage=15, freeboy post.