How to make bootable a USB stick with installation media of openSuSE (12.3), using syslinux

There is a custom case. We have formatted fat32 usb stick. We would like to keep untouched files on the stick, i.e. simple dd if=...iso of=usb_stick_device is not fit to us.
So, the next is how to...

1. Download installation media and copy it to the root directory of the stick.

2. Run

syslinux /dev/stick_device

dd if=/usr/share/syslinux/mbr.bin of=/dev/stick_device

Mark the partition on the stick active using fdisk or parted or other tools.

3. mount usb stick and installation media.

4. Copy from isntallation media catalog /boot//loader into /boot/syslinux

5. create file /boot/syslinux/syslinux.cfg like 

default linux
label linux
kernel linux
append initrd=initrd ramdisk_size=512000 ramdisk_blocksize=4096 install=hd:/openSUSE-12.3-DVD-i586.iso

6. Boot from usb stick and perform installation.