set ‘Auto Proxy Discovery’ from command line?

Hi, I am putting together some 'firstboot' scripts and was wondering if there is a way to set the 'Auto Proxy Discovery' option under Mac OS X 10.6.x via the command line? Currently, I am using: networksetup -setautoproxyurl "Ethernet" http://wpad.wpad.dat But the above only sets the 'Auto Proxy *Config*' and does not do anything with 'Auto Proxy Discovery'. Is it possible to set 'Auto Proxy Discovery' via the command line? thx! Maria