2004 Hitachi ZX75US with Stanley HS60 hoepack compactor connection

Just picked up a 2004 Hitachi ZX75US that came with a Stanley HS60 hoepac compactor, but I've got no documentation on how to set it up or operate it. The seller says it was used on this machine before. I've got plenty of excavator experience but have never worked with a hoepac.

The HS60 has two hoses with male quick connects, and the excavator's stick has female quick connects on both sides along with bypass valves to switch from thumb to hoepac. The compactor itself has IN and OUT ports labeled on it.

My plan was to connect the left hose to the left side of the stick and the right hose to the right side. That would route the hydraulics from the cap/piston end of the thumb cylinder into the IN port, which seems right to me.

I don't see any kind of single direction mode switch or valve on the hoepac anywhere. If I'm hooking this up correctly, how do you stop someone from accidentally running it backwards by hitting the wrong button on the joystick? Does that make sense?

The bypass valves, when positioned right for the compactor, create a one-way circuit. Breaker attachments work the same way. On Hitachis, the feed line usually runs on the left side of the boom when you're looking out from the cab.