PXE boot in F17 has changed considerably?

[Mark Zhitomirski]

Hi!

I've got used to installing Fedora 15/16 via PXE by simply putting/modifying a couple of lines in pxelinux.cfg/default like these:

LABEL Fedora16
    MENU LABEL Install Fedora 16 x86-64
    KERNEL fedora16x64/vmlinuz
    initrd fedora16x64/initrd.img

vmlinuz and initrd.img were taken from 
linux/releases/16/Fedora/x86_64/os/images/pxeboot/
in case of F16

However when i do the same with files from 
linux/releases/test/17-Beta/Fedora/x86_64/os/images/pxeboot/
or
linux/development/17/x86_64/os/images/pxeboot/
i get the following errors (both on a real and on a virtual machine):
====
dracut: anaconda using disk root at /dev/sr0
dracut Warning: Couldn't mount /dev/sr0
dracut Warning: no suitable images
dracut Warning: /dev/root does not exists

Dropping to debug shell
===

Is this the expected behavior and was it discussed / documented somewhere?  

Regards,
-- Mark