this is the unique pxe start file for a server:

DEFAULT xen6
LABEL xen6
 KERNEL img/xen650/mboot.c32
 APPEND img/xen650/xen.gz dom0_max_vcpus=2 dom0_mem=752M com1=115200,8n1 console=com1,vga --- img/xen650/vmlinuz xencons=hvc console=hv0 console=tty0 answerfile=http://172.16.1.12/pxe/sys/00-50-56-11-08-01/xen6.xml install --- img/xen650/install.img