You'll need to add this inside ItemDef.java in the client side. Also you'll need to add the model file into the Raw folder.
Code:
case ####: // Pick your own case id.
itemDef.itemActions = new String[5];
itemDef.modifiedModelColors = new int[1];
itemDef.originalModelColors = new int[1];
itemDef.itemActions[1] = "Wield";
itemDef.modelID = 5412;
itemDef.anInt165 = 51797; // Male
itemDef.anInt200 = 51819; // Female
itemDef.modelZoom = 840;
itemDef.modelRotationY = 280;
itemDef.modelRotationX = 0;
itemDef.modelOffset1 = -2;
itemDef.modelOffset2 = 56;
itemDef.anInt204 = 0;
itemDef.name = "Lime Whip";
itemDef.description = "Custom description here.".getBytes();
itemDef.modifiedModelColors[0] = 17350;
itemDef.originalModelColors[0] = 528;
break;