Uploading supplementary material to figshare. How to refer to it before making it visible to the public? My problem is the following: We want to upload supplementary material for bookchapters I'm editing. We have decided to use figshare.com for this. One advantage is that they supply all material with a DOI. But (as far as I understand) they do only so when material is made available for the public, not for private data.

Now, it would be a little strange to make supplementary material available a long time before publication (possibly more than a year).

How may I obtain a permanent reference (doi, link, etc) to the supplementary material which I can add to the respective bookchapter already without making said supplements visible to the public?

And if this is not possible, what would be a workaround? Make it public just shortly before handing in the edited volume to our publisher (this would still be months before the publication date)? Just refer to the account (not a single file) on figshare the material will be hosted on? Include a placeholder DOI within the chapter and include it after we received page proofs from the publisher? Just publish the supplementary material already because nobody cares?
At the bottom of the Edit Item screen is an option to create a private link. There's more info about private links on their blog.

For peer review, the private link feature has the added advantage that it hides the author information.