linux - How to use Syslinux to chainload Ubuntu installation?

I try my best to detail my question. If it would run out of your patience, go to lastest paragraph.

I downloaded Ubuntu 13.04 from its official site and extracted files to a folder ubuntu\ on USB stick( Z: for example). So files are now in Z:\ubuntu\

Before that, I downloaded Syslinux 5.10( 6.00 has bugs) and used it to install boot code to USB stick with this command:

syslinux.exe --mbr --active --directory /boot/syslinux/ --install Z:

Then I copied chain.c32 and required libs to Z:\boot\syslinux and added to syslinux.cfg( unimportant part is ignored):

COM32 chain.c32

APPEND isolinux=/ubuntu/isolinux/isolinux.cfg

Syslinux booted successfully but failed to boot Ubuntu, saying:

Err: option 'maps' requires a sector'', but I didn't know what it meant.

Then I tried loading Ubuntu's isolinux configure using:

config /ubuntu/isolinux/isolinux.cfg /ubuntu

But only got message saying:

Loading gfxboot... Failed: No such file or directory

I tried again with:

config /ubuntu/isolinux/isolinux.cfg /ubuntu/isolinux/

And it said:

Failed to load COM32 file gfxboot.c32

But I could see LABELs with [TAB] Key:

boot:

live live-install check memtest hd mainmenu help

So I tried booting Ubuntu via command line:

boot: live

And it showed that:

Loading /casper/vmlinuz failed: No such file or directory

I think Syslinux recognizes Z:\ as root directory /, not Z:\ubuntu\, so it failed to load vmlinz. So I moved files to Z:\ and reboot. Though syslinux still failed to load gfxboot but I booted into Ubuntu successfully with

config /isolinux/isolinux.cfg /isolinux/

boot: live

I don't understand why it could not load gfxboot.c32 when it read isolinux configure correctly. Maybe syslinux I use and isolinux Ubuntu uses are not the same, and the bootcode and gfxboot are not compatible.

Syslinux Wiki mentions that CONFIG can restart the boot loader using a different configuration file and set new home directory using:

CONFIG /path/to/cfg/file/configfile.cfg /path/to/new/base/dir

I followed the guide but filed to let Syslinux set Z:\ubuntu\ as root directory. Maybe I misundertood this guide.

So my question is, how to put Ubuntu or other Operation System into a standalone folder and configure syslinux properly to set direcotry where Ubuntu or other OS is as root directory so that I could boot the OS successfully?

Ok, after assembling facts and re-re-reading question and our discussion: You can't install Operating system to "folder" (That is, you can't install Linux to folder like /ubuntu/, you need to install it to/folder). Linuxes want a full featured partition: they need to put/usr,/var`, on root of what they see as filesystem. (chrooting aside)

Also, Linux can't be installed on FAT-32. This file system lack symlinks and some other facilities which are bedrock of Linux operation.

You need ext3/4, xfs or other supported real filesystem. However, you can just install ubuntu on usb like on any normal hdd - just setup: fat32 or ext2 partition for boot{manager,loader} and kernel image, and ext4 for operating system. You'll be able to apt-get programs on in, save documents and whatnot.