Enabling DK's if server expansion set to 1?

[sarge816]

We've got a LAN server for family/friends which is semi-progression, where we're locking the server at expansion 0, then 1 and completing all content before moving on. We're currently in TBC and it's been requested to open up the DK class while the server is still locked to expansion 1 in the conf. This disables getting to Northrend of course, and also DK is not available in character creation. I saw Chromiecraft enabled DKs before officially opening Northrend, any way to easily accomplish this that I'm not seeing? I could just enable expansion 2 if I could keep people out of Northrend since the server is capped at 70 anyways.