kickstart from USB stick

I am using cobbler to install a new red hat 5. (I know it is a bit old)
From the network , it is working perfectly.

I would like to use a USB stick
The USB stick is generated , the ks.cfg files are existing in the root folder as well as is in the isolinux one.

As a first step, I am using a VM (vmware workstation) before using the target HW

I have been looking around to find the right command line in the isolinux.cfg file but none of them worked .
I got an error message saying a kickstart not found

Any suggestions ?

I tried :

append initrd=initrd.img ks=hd:sdb1:/isolinux/ks.cfg ksdevice=bootif lang= text
or
append initrd=initrd.img ks=hd:sdb1:/ks.cfg ksdevice=bootif lang= kssendmac text
or
append initrd=initrd.img ks=hd:sda1:/isolinux/ks.cfg ksdevice=bootif lang= kssendmac text
or
append initrd=initrd.img ks=hd:sda1:/ks.cfg ksdevice=bootif lang= kssendmac text
or
append initrd=initrd.img ks=file:sda1:/isolinux/ks.cfg ksdevice=bootif lang= kssendmac text
or
append initrd=initrd.img ks=file:sda1:/ks.cfg ksdevice=bootif lang= kssendmac text
or
append initrd=initrd.img ks=file:sdb1:/ks.cfg ksdevice=bootif lang= kssendmac text
or
append initrd=initrd.img ks=hd:/dev/sda1:/ks.cfg ksdevice=bootif lang= kssendmac text

cheers