I had the same issue and hunted everywhere for a solution. After countless hours of trial and error I have solved the issue.
1. Log into nas, go to network-printer manager, to see if it is recognised by the nas. If it is it will show up.
2. Windows start bar, go to devices and printers and click add printer.
3. Choose add network, wireless or bluetooth printer.
4. Stop the search for printer then click on, the printer i want isnt listed.
5. Choose, select a shared printer by name.
6. Type in bar, \\xxx.xxx.x.x\printer_name
where xxx.xxx.x.x is the nas ip address, and printer_name is the name as it appears in the printer
manager from step 1.
7. It should now work. Print a test page to see.
Also is worth mentioning that I had to use a static ip for the nas as on previous occasions the ip changed and mapped drives would no longer work and had to be deleted and re-added, which would also then cause printer to not work as ip had changed.
Dont worry about port forwarding on your router, you shouldnt have to do it.
