It's really a waste to use the package simply for the diode, unless you pick them up super-dirt-cheap (which it appears you did), AND the IGBT isn't blown up (shorted).  IGBT's are very static sensitive by nature.  Their actual construction is much closer to a MOSFET driving the base of the transistor base. Transistors are current driven by their base, whereas MOSFETS are voltage driven on their gate.  So, they married the two technologies.  The internal MOSFET design switches the (sometimes significant) base current, whereas the gate of the mosfet is driven with a plain 'ole voltage source (usually +- 12v, up to +- 30v).  

Those would be just dandy for building your own multi-kW output inverter with, too. :)  If you were so inclined...