WPAD = Web Proxy Auto Detection (also know as PAC = Proxy Auto configuration)
If you wish the browser to auto-detect the WebTitan proxy settings you need to amend your DNS settings and configure a DNS record for WPAD e.g. You could add the following as a DNS A record
Note: If setting up WPAD using DNS on a Windows Server you may need to remove wpad from the dns global black list. To check if it's on the blacklist from a command window on your Windows Server type:
dnscmd /info /globalqueryblocklist
To remove see:
When you enable "Automatically detect settings" in your proxy settings (Control Panel >Internet Options >Connections > LAN Settings) your browser will perform a DNS query for wpad when it is opened. If wpad can be resolved to an IP address your browser will connect to that IP and download a file called wpad.dat. This file will contain the settings your browser needs to connect to and use WebTitan.
The WPAD wizard is located in System Setup > Autoconfiguration. You can also edit the WPAD file from there.
This site has excellent documentation on the various WPAD commands: