I have opened 2 threads at Microsoft's places already:
http://forums.iis.net/t/1208163.aspx?IIS+8+0+Enable+FXP+in+IIS+FTP+
But no one seems to be able to help me, or know the answer. As I have mentioned I read the 7.5 documentation but I can't find any options within IIS 8.5.
PASV port range is enabled and the FTP does work. If I try to FXP I get:
(17:40:23) [2] 501-Server cannot accept argument.
(17:40:23) [2] Win32 error: The parameter is incorrect.
(17:40:23) [2] Error details: Client IP on the control channel didn't match the client IP on the data channel.
(17:40:23) [2] 501 End
which of course is expected since I haven't enabled FXP