fortigate transparent to explicit proxy

Hello,

I have a fortigate 5.0 cluster (active/passive) configured in transparent mode with SSO policies (+ antivirus, webfiltering, app control..) and VDOMs.

Can someone point me to the right steps in order to switch from transparent to explicit proxy configuration ? I have Explicit Proxy tab under root VODOM/Sistem/Network/ is that all to configure ? probably not..