There's no selector port on my '11 M7040. I just plug single or double acting cylinder into breakaways and raise/lower cylinders. Do you have breakaway couplers seated properly??
Check your "books" I think that using a single acting cyl. requires using the proper (flow) direction outlet. On one (JD) tractor I had, I had to only partially move the valve lever with the single acting cylinders to lower.