Nick, I'm having the same issues. I know this is an old.post but what did you discover? My orbital valve also only has 2 lines coming out of it.
Nick,
Unless the steer orbital is mounted to the hydraulic valve, you should have two lines for hydraulic flow and two lines for cylinder. The pressure line normally comes off a hydraulic fitting tied into the hydraulic system. Without a serial number, i cannot tell you exactly where all connections are for your lift. Thanks.