I'm not sure if we talk about the same things: WPA(2) wireless encryption is working fine, just enter your settings in the web interface at "Wireless"/"Interface"/"Authentication Method" and you have a range of encryption methods available.
It becomes a bit more complicated if you want to have the WL-HDD as a client in a wireless LAN. Then you have to do the above mentioned steps additionally for the matter to work.

Hope this helps, unfortunately, I can't test it myself anymore because I'm now using it wired only because performance is much better rather than with wireless.

F.