[lerxst2112]

Try changing this:

struct Merchant_Sell_Struct {
/*000*/    int32 npcid;			// Merchant NPC's entity id
/*004*/    int32 playerid;		// Player's entity id
/*008*/    int32 itemslot;
           int32 unknown12;
/*016*/    int8  quantity;		// Already sold
/*017*/    int8  Unknown016[3];
/*020*/    int32 price;
};

To this:

struct Merchant_Sell_Struct {
/*000*/    int32 npcid;			// Merchant NPC's entity id
/*004*/    int32 playerid;		// Player's entity id
/*008*/    int32 itemslot;
           int32 unknown12;
/*016*/    int32 quantity;		// Already sold
/*020*/    int32 price;
};

That might actually break something, but cross your fingers and prepare to change it back.