Firewal question?

Is there a way to enable the firewall in 10.7 via Applescript? If it is possible is there a way to check if the firewall is already enabled and if it is not turn it on. I tried to do it via GUI scripting but I could not target the Firewall tab for some reason. I Can only target the General tab.

This is all I got so far

example:

tell application "System Preferences"
	activate
	reveal anchor "Firewall" of pane "com.apple.preference.security"
end tell

Thank you in advance for any help I have been stuck for a while.