ISPConfig for LAN use only ?

O.K. This is the thing

I have Hughes net Satellite internet and they do not allow anyone to run a server of any
type, but that's ok.

My Hughes net is plugged into a Linksys WRT-54G flashed with DD-WRT
I share my internet connection with 9 other wireless users all is fine and dandy

Now using Falko's Perfect ETCH setup and ISPconfig “All installed Perfectly”
and working fine “hold on here it comes” BUT I can't nor do I wish to be able
to have the server accessible from the outside world only via the lan.

I have the linksys DMZ pointing to the static server IP and the local DNS
doing the same, Don't remember the rest of it but it worked hit and miss,
sites like http://lan.brad.net, http://lan.fred.net etc. etc etc. some times came up just fine,
http://192.168.1.50 “The Server” came up shared IP “That's fine”.

How do I make ISPConfig serve up the pages reliably ?
Linksys port forwarding 80 > 81 ?
Use https://lan.brad.net ?
Change bind9, iptables, Apache, Mysql, PHP ?

BIG thanks for any help