I had a similar idea, to connect a docking station directly to my Syno DS212j,
http://www.amazon.co.uk/gp/product/B00D1NR9MA?psc=1&redirect=true&ref_=oh_aui_detailpage_o06_s00 every now & again, the connection would drop out.
After several emails to Inatek, they decided conecting to a NAS was not supported.
I then tried to use it to clone a drive this didn't work, & I sent it back.