1. Enable ICAP Patience Page on ProxySG. This can be done by going to the Management Console > Configuration > External Services > ICAP Feedback to enable "Return patience page".
2. Disable compression support on ProxySG so that the res.magnus.de will send uncompressed traffic to it. The uncompressed traffic will be sent to the ProxyAV for Apparent Data Type detection.
define action NoEncoding