I think I've already done what you're suggesting and it's not exactly what the problem is (at least so I think).
Let me break it down for you with a little more detail and some pictures.
On my AI object, I have this script. I want to use a variable in Playmaker to provide the gameobject that should be placed inside. I can drag a Gameobject from the scene (as shown) into this field and it works perfectly.
This is my FSM where I am finding all of the game objects with a specific tag and then pulling one at random. The playmaker array doesn't have an option for "Object", but it does for Gameplay. The object I want to be placed in there is a gameplay object so that seems like a good idea.
If I try to pull an "object" type from the array it doesn't find or store anything. So I have to use a gameplay object.
In this last part of the FSM, I'm attempting to set the "Route" property on the script. Gameplay objects aren't recognized, but if I make an object variable of the type "apex.Steering.Props.PatrolRoute" it IS recognized.
So - I seem to only be able to store and pull gameobjects from my array and set property on the script only takes objects of a specific type.
I don't know how to translate between the two. Does that make sense?