I'm running SliTaz in base from from a USB flash drive and trying to build an image which will eventually be loaded to an internal flash drive. I need to create a permanent mount point for an external drive (SCSI), but whenever I create a new mount point, then create the new filesystem image (tazusb writefs gzip), the mount point has vanished. I initially created the mount point in /mnt/, but then discovered that the init process loads a new filesystem onto mnt; I then created a new folder /mount/ and put my mount point in there, but /mount/ disappeared after writing the filesystem and rebooting.
Where is the correct place to put a mounting point that will be preserved in a persistent image?

What version of SliTaz are you running? I'm not an expert but can maybe provide some assistance.

Is anything you download / install persistent?
When you created the flash drive did you also create an ext3 partition?

Running SliTaz 4.0, kernel 2.6.37.
Yes, packages installed are persistent, as are changes to files in /etc/. I discovered that the problems was that the tazusb utility doesn't scan / for folders to copy to the compressed filesystem. The problem was fixed by adding the mount point base folder to the list of directories that tazusb checks prior to building the compressed filesystem; tazusb is a script file, so the changes were easily made.

Sounds like you are running a Live CD on the flash drive which is giving you expected behavior, lose everything on re-boot. What method did you use to get Slitaz on the flash drive. Doesn't seem like an actual install or an install with persistence.