displayName for items doesn't work

[Former user]

id = 6000; name = "mysword"; displayName[0] = "New Sword"; addToCreative[0] = true; creativeTab = "combat"; textureFile[0] = "sword_1.png"; damage[0] = 5; full3d = true; usingAction[0] = "block"; maxUsingDuration[0] = 72000; effectiveBlocks = "30"; harvestBlocks = "30"; efficiency[0] = 6.0; maxDamage = 160;

onHitEntity[0] = "itemstack.damageItem(1);"; onRightClick[0] = "player.setItemInUse();"; onBlockDestroyed[0] = "itemstack.damageItem(2);";

My item always get "unnamed" name.