(I removed the non-working Atheros AR5BXB63)
100% working as ethernet adapter and using Realtek Utility.
Easy and simple.
1.- Download attachment.
2.- Install "Installer87se.pkg"
3.- Leopard will now detect new network adapter.
3.- Configure it as new Ethernet adapter in network preferences.
5.- Realtek Utility should auto start.
6.- Detect networks, join and enjoy!