[Users] How to pxeboot ovrit node into memory automatically?

Hi, I was following the instructions at http://www.ovirt.org/Node_PXE. My goal is to use pxeboot (iPXE) to boot the node entirely into RAM with rootfs. What I got now is an installation screen which requires a local storage. My system has no disk and this doesn't quite work for me.  What's are the kernel parameters I need to use to boot the node into RAM automatically?  I am OK as the first step with a stateless node.  David