yeah its built into that kext
try EthernetBuiltIn=Yes at boot
Thanks for the info. I tried the EthernetBuiltin=Yes at boot, but to no effect I'm afraid.
I have solved the problem though, by adding lnx2mac's Realtek kext.
After a reboot, the network came straight up. I'm streaming an Internet radio station through iTunes as I type this.
As an aside, I purchased a Apple Magic Mouse today and a wired keyboard, both of which are great. I tried an Asus BT211 dongle (as opposed to the BT21, which I'm told works out of the box), and it didn't work. I replaced it with another from a Windows machine that I can't vouch for the make of, and it worked first go. So, the lesson here is that the Asus BT211 does not work out of the box. Probably someone has a kext.
Thanks again for the help!