I couldnt find your specific model per se but some similar models I suspect that will probably have similar instructions. At the very bottom-right of the following page you'll find models of Zyxel listed. Click on model no.(s) links in brown text that are most similar. This will take you to another page & choose the link in brown text called 'Port Forwarding for the ZyXEL ...' You'll need to set up a static ip but a link to the instructions will be there: http://www.portforward.com/routers.htm Use Port 6346
I did also find this but probably not needed: Search results for port forwarding ZyXEL 642M-11

You will also need to Force IP within LW: Force IP instructions & sample image

This will give LW full access & not just partial. Some hints on optimising LW: A well set-up LW can start to automatically continue its dwnlding after it's settled down perhaps 2 out of 3 times you open LW. Optimising LW & Maximising Uplds & Dwnlds A (1st post only) & also Part B which is even better & last & least are search & dwnld hints.