Syslinux - Mar 2008 - How to use syslinux to mount initial ramdisk as root file system and mount NFS to "/mnt/nfs"?

I know this is not a question for syslinux itself, but a question for
syslinux usage on Linux.

I use pxelinux to boot Linux. I know I can use "root=/dev/nfs
nfsroot=ip:/dir" to mount the NFS as root file system. But it needs me
to prepare several different directories for different clients and
each directory should include a initrd.gz copy (e.g., cp/mv/mkdir
utilities, etc).

My requirement is: mount initial ramdisk as root file system and mount
NFS to "/mnt/nfs" so that different clients can share the same
initrd.gz and their NFS directories will not include initrd.gz
contents (e.g., cp/mv/mkdir utilities, etc)

I find that KNOPPIX has a "nfsdir" kernel parameter to satisfy this
requirement, but it is not supported by the mainstream linux kernel
(e.g., I am using SLES10 kernel).

Any comments are welcome!