Manually adding file to sych folder


I have a 500 GB of data to sync with owncloud server.
I tried to rsynch from my desktop to owncloud server. And then found out this beautiful line
The data directory on the server is exclusive to ownCloud and must not be modified manually.
( that one cant sycn data internally. Though the post is 3 odd years old.
Now I am in a situation that my 500 GB in my ownclod data folder but not visible/sych to other clients :). Do we have any solution/workaround ?
owncloud server version 10.0.2 (stable)


I just had a short look at the link and it seems to me two solutions/workarounds are provided there under the "Alternatives" headline.