I have an e-smith 4.1.2 setup with Blueyonder..... works like a charm.
I had a little bit of grief getting it running to begin with - it took a bit of fannying around to get Blueyonder to recognise the NIC. Sounds like you've got the NIC registered OK if you have it running in M$.
I got in a mess to start with - I tried to only register the one MAC address, and then swap over the internal/external NICs in e-smith. That was a bad idea, the solution..... register both your NICs with Blueyonder. Make sure e-smith is setup with defaults, then wait for a day or so (for the MAC addresses to filter through BY's system), leave your CM off overnight, fire it up in the morning and all should be dandy.
Like the NTL guys, there's a few e-smith users in the blueyonder.comp.linux newsgroup.
I'll keep my eyes open for followups, and will help you where possible.
Ritchie