My portable music player is formatted with hfsplus. The linux hfsplus mount this default readonly. To mount it writable you have to mount with the force option. I tried it as root on the console with the following mount options “rw,uid=1000,gid=1000,force”. This worked. Now I want to make it the default for this device. I opened nautilus on the device as non root user and added these options to the mount preferences. On a new connect I got the error message: Wrong mount options. I tried “gnome-mount -vvv -b -d /dev/” on console. gnome-mount is the tool used to mount the devices. I got the debug message that there are not allowed mount options. I read the man pages and found out that uid is set by gnome-mount itself and rw isn’t allowed with uid. So I removed rw, uid, gid options so that only force is added. Now the ipod with hfsplus is mounted writable on connecting to the computer.

Update: By looking through the gnome-mount code I find out that you can set the uid option like uid= and this is replaced with uid=<id of the current user>.