I too have the black screen issue and have followed the video and all documentation with no luck.  MY security server is listening on TCP/UDP 4172 and I have opened up HTTP, HTTPS, and 4172 TCP/UDP on my firewall to the Security server.  In my setup the Security server is just on the local LAN, not in a DMZ and is a domain server.  there is no firewall/router between the local view desktops, ESX servers, or vCenter server and the Security server.  the box for PCoIP gateway is checked.  all works internally and RDP works externally but PCoIP does not.  I am using a SonicWall NSA 2400 and it appears that all the correct ports are open as i can telnet from outside to the Security server on 4172 and HTTP/HTTPS are working correctly to it.  any other thoughts or ideas that might help me out?  thanks!