The associated Files and Folders for a Project is only supported with the Trimble Connect workflow - you will find that it is grayed out in the TCC option if you select that as the external service you are using. I assume that the TCC workflow was not supported because we will be moving things over to the Connect Platform once the upcoming Works Manager makes the transition to the Trimble Connect Platform.
I have tested the Connect Workflow and it works well for small Projects, however if you have a Large Point Cloud and Large Otrthophoto which has been "Tiled" then you will find the Save File Remotely a little slow because it is copying literally hundreds of files across the web - I suggest that creating a project Archive or a Zip File of the data that you want to share would be quicker than the Save Remote File / Open Remote File workflow as it is defined today. I have logged in some issues / flaws that I see with the way that this extended files and folders was implemented in the hopes that we can make this faster (for example the Image Tiling is not needed in the Transfer since the raw Orthophoto is transferred and the receiving system will set its own Image Management settings (Support - Options - Images) and retile the orthophoto as needed anyhow - and that alone accounts for >50% of the data and likely 90%+ of the files that are being transferred.
Hope this answer the question
Alan