JD 5420 rear remote upgrade

[Deere5420]

On my 5420 (IOOS model), I currently have 2 rear remotes and am looking at upgrading to a 3 remote unit. On top of the right fender is where the handles are, and there is an empty slot for a 3rd lever. I took the cover off and found the bracket will accept the 3rd handle and cable. On the rear, the valve block assy has a tag on it that says the manufacturer is Sauer Danfoss, with a 2 numbers on it. Top line says-054C, bottom line says 156B7056. I've searched the net for this and came up with nothing. Called the Deere dealership this morning, and to upgrade with the factory parts is over $1500. Don't know if it's worth that. Just seeing if anyone has any input on where I may be able to find what I need without having to get it from JD, as they are getting the 3 valve remote from somewhere. Thanks. For some reason, the pic got turned. The orange triangle should be at the top of the picture.