Hi,
I've found a very good solution for adding wireless network functionality to your Beosound 5:
Asus wl-330gE
http://farm4.static.flickr.com/3323/3262426782_109da7054f.jpg?v=0
It fits in the palm of your hand!
It can act as different devices (e.g. Access point, Ethernet->Wlan-Adapter ...). This is a product where somebody though till the end :-)
You set it up on your computers browser. Enter your wireless network details and save them to the unit.
If your Beomaster 5 is within the range of your wireless network you plug in the mini ethernet Lan cable supplied with the Asus wl-330gE plus the USB power cable into your Beomaster 5 and a few seconds after the Asus powered up, you're connected to your wireless network without any driver installation etc. on your Beomaster 5.
if your Beomaster 5 is NOT within the range of your wireless network you can use a standard ethernet lan cable to connect the Asus wl-330gE with the Beomaster 5 on a location where the Asus adapter is in range with your wireless network. In this case you can use the power adapter (supplied) for your wall outlet.
I'm very happy with this solution and I can clearly recommend it!