starting xdm at boot on headless box via rc.d script?

[Anton Shterenlikht]

I've a headless server that accepts
connections via XDMCP. I'd like to
start xdm in daemon mode without
attaching it to any virt. terminal.
>From the command like I can simply
type xdm, but can I do this via
/etc/rc.conf, something like xdm_enable=YES?

I see some examples of using custom
scripts in /usr/X11R6/etc/rc.d, e.g.:
http://terrencemiao.com/Webmail/msg00720.html

Is this a good idea?

Thanks

Anton