Chapter 1 What’s New for FortiOS 5.0 : New features in FortiOS 5.0 Patch 3 : URL-based Web Proxy Forwarding
  
URL-based Web Proxy Forwarding
In order to configure URL-based web proxy forwarding, WAN Opt. & Cache must be enabled using Feature Setting. For more information, see “Feature Select”.
FortiOS now supports URL-based web proxy forwarded, which is required for explicit proxy installations using Threat Management Gateway or Blue Coat.
URL-based web proxy forwarding can be configured by going to WAN Opt. & Cache > Cache > URL Match List.