Debian usbmount

Install usbmount
There is nothing special here, you will also need module-init-tools for automatic kernel modules loading apt-get install usbmount module-init-tools then update module list and reboot depmod -ae && reboot

configuration
If you want to automount vfat devices, edit usbmount configuration : nano /etc/usbmount/usbmount.conf // replace FILESYSTEMS="ext2 ext3" // with FILESYSTEMS="ext2 ext3 vfat"

By default, usb disks will be mounted to /media/usb0 to usb7, if you want to change that replace : MOUNTPOINTS="/media/usb0 /media/usb1 /media/usb2 /media/usb3             /media/usb4 /media/usb5 /media/usb6 /media/usb7" with what you want (do not forget to create the directories)

dynamic symlinks
If you want a symlink to appear in the Samba share when a device is automatically mounted you will need to edit the scripts in /etc/usbmount/mount.d and /etc/usbmount/umount.d. Note, use the path to your shared directory, it may be different from mine.

Edit the mount.d script: nano /etc/usbmount/mount.d/00_create_model_symlink

Add the following to the symlink creation section of the script: test -e "/mnt/disk1/share/$name" || ln -sf "$UM_MOUNTPOINT" "/mnt/disk1/share/$name"

Edit the umount.d script: nano /etc/usbmount/umount.d/00_remove_model_symlink

Add the following section: ls /mnt/disk1/share | while read name; do   if test "`readlink \"/mnt/disk1/share/$name\" || :`" = "$UM_MOUNTPOINT"; then rm -f "/mnt/disk1/share/$name" break fi done