Hi @MichaelSzabo, I am sorry we do not have the Asset Manager type of capability ready yet. In the meantime, one option is for you to use a CDN service like Amazon or Rack Space, then create a CNAME record in your DNS settings for your domain, to point a subdomain of your primary domain to the file storage.
For example, if I have a site called mysite.com, and a pdf file in Amazon S3 in a bucket, I would go to my DNS provider and add a CNAME record for files.mysite.com and point that at the public CDN file storage address. Then you can put your files there and link it like : http://files.mysite.com/myfile.pdf
I hope this helps, I know it can be frustrating to wait for new features. I do not have an exact ETA yet for this kind of Document File Upload storage in Webflow yet. Cheers, Dave