Actually there's a low effort way to zero the prop.

1) Import the prop to Poser

2) Manually position it where you want it to be when it's zeroed. You can scale it too

3) File > Export > OBJ ... Then select the object you want to export

4) On export options check "Include existing groups" and "Preserve existing material names". Uncheck all other options.

5) Save the new OBJ

6) New scene

7) Import the OBJ you just created

That's all. OBJ is not zeroed where you want it to be. The same trick can be used to fix scale and orientation too.