Remote modules for inverters are often installed as optional equipment. Owners manuals are usually pretty generic and often contain directions on how to operate something, even if it's not installed. I'm not saying you DON'T have a remote module, I'm just saying that, just because your owners manual shows you how to operate it, doesn't necessarily mean it's installed.
If you have a remote module/on-off switch, you should be able to trace the wires from the inverter itself, and see where it's installed. The harness will usually be thin gauge wire(s).
Kev