Web Proxy Server Changes (http) OS X

I am about to do a bulk change of web proxy Servers, activating through Apple Remote Desktop, but can’t work out a script to automate this. Does anyone have any ideas. So far I have got to:

tell application “System Preferences”
activate
set current pane to pane “com.apple.preference.network”
end tell

But can’t get any further to add the IP adress and port numbers to the web proxy server setting under the airport selection. Would be very grateful if anyone has any ideas.
thanks in anticipation…
Simon