Metarepository/Software Packages for NSA320

Greetings,

I got a working NSA320 and got it set up with 2 HDs alright. Now I would like to install some applications, like Plex Server, on the NAS. I have read this forum for instructions and tried to install the metarepository with web_prefix file (no file extension), both onto Make subfolder ant the parent folder.

http://zyxel.ddnss.eu/Users/Mijzelf/zypkg-repo/

OR

http://zyxel.ddnss.eu/Users/Mijzelf/zypkg-repo

OR

https://zyxel.ddnss.eu/Users/Mijzelf/zypkg-repo/

OR

http://zyxel.ddnss.eu/Users/Mijzelf/zypkg-repo

I have also tried by writing these both to the ZYPKGS file. No matter what, fetching the repo contents always fails.

Firmware is V4.70(AFO.4)

I have no more ideas how to proceed, so I would be very grateful for your assistance with this problem.

Ps. Is there a way to download a package and install it manually? Is there a newer firmware for this box somewhere available?

Thanks in advance.