[CentOS] Intel D425KT Motherboard / Realtek RTL8105E

Greetings-

I'm attempting to get CentOS 5.5 x86 (yes, very specific version required for specific software usage scenario... don't ask) running on an Intel D425KT mini-ITX motherboard. Everything works fine, with the exception of the onboard ethernet, which is a Realtek RTL8105E chip. The stock CentOS installation attempts to use the r8169 driver, which does not work. I've been around the block a few times dealing with Realtek interfaces and their driver hell, but this one is stumping me.

Things tried so far:

-Adding pci=assign-busses to the kernel parameters
-Installing kmod-r8101 from elrepo, old and new versions
-Compiling driver from scratch direct from Realtek

In every test, I end up with what *appears* to be a functioning ethernet interface (r8101 driver detects chip as RTL8105E correctly), or as reported by the software (ifconfig, ethtool, etc). But, I just cannot get any traffic to pass. There is a link light for the ethernet interface, but no actual activity when testing.

Any thoughts?

--Tim