If you go to DBCStructure.h and search for the dbc entry structure, you can view the column names:
Since they show up as 0 which I'm not sure why either, you can look in the code to change this.
#define MAX_OUTFIT_ITEMS 24
//uint32 Id; // 0
uint8 Race; // 1
uint8 Class; // 2
uint8 Gender; // 3
//uint8 Unused; // 4
int32 ItemId[MAX_OUTFIT_ITEMS]; // 5-28
//int32 ItemDisplayId[MAX_OUTFIT_ITEMS]; // 29-52 not required at server side
//int32 ItemInventorySlot[MAX_OUTFIT_ITEMS]; // 53-76 not required at server side
Add the gear you want to in playercreateinfo_items, after that go to Player.cpp and add:
to this line:
if (oEntry->Class == 6)
It will prevent loading the death knight outfit.