Welcome to the forums, and great question!
The integration is not provided by us, so I can’t say if there is a specific issue with this engine that is preventing it from working. However this a question I see now and again about the Loader and other file types, so I suspect this is a case of making sure it’s configured correctly.
I would say this section of the pipeline tutorial would be a good place to start, if you want to see an example of how to add a different file type.
You need to make sure you have defined action mappings for the
PublishedFileType to the action you want it to be able to perform.
And if the available actions can’t handle fbx importing then, you will need to write your own custom action that can do that.
Hope that helps?