EntitySpawnPacket Invisible ?

Hi,
I'm trying to make an AntiCheat. It does work good, but i got just one problem: Bot invisibillity.
I'm sending a PacketPlayOutSpawnEntityLiving to the player and everything works, except of the invisibillity. I tried to fix it with Protocolib, but i dont really know, how to use it.
Could someone help me out ?

EDIT:
I'm using this code:

Code:

public void sendPacket(Player p, WrappedDataWatcher wdw) {
        @SuppressWarnings("deprecation")
        PacketContainer newPacket = new PacketContainer(24);

        newPacket.getIntegers().write(0, 500);
        newPacket.getIntegers().write(1, (int) wdw.getEntity().getEntityId());
        newPacket.getIntegers().write(2, (int) (p.getLocation().getX() * 32));
        newPacket.getIntegers().write(3, (int) (p.getLocation().getY() * 32));
        newPacket.getIntegers().write(4, (int) (p.getLocation().getZ() * 32));
        // write(0, 500).
        // write(1, (int) EntityType.GHAST.getTypeId()).
        // write(2, (int) (p.getLocation().getX() * 32)).
        // write(3, (int) (p.getLocation().getY() * 32)).
        // write(4, (int) (p.getLocation().getZ() * 32));

        newPacket.getDataWatcherModifier().write(0, wdw);

        try {
            ProtocolLibrary.getProtocolManager().sendServerPacket(p, newPacket);
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
    }

    public WrappedDataWatcher getDefaultWatcher(World world, EntityType type) {
        org.bukkit.entity.Entity entity = world.spawnEntity(new Location(world, 0, 256, 0), type);
        WrappedDataWatcher watcher = WrappedDataWatcher.getEntityWatcher(entity).deepClone();

        entity.remove();
        return watcher;
    }

and i got this Exception:

Exception (open) Exception (close)

org.bukkit.command.CommandException: Unhandled exception executing command 'api'
in plugin TestServerAPI v1
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[spi
got.jar:git-Spigot-db6de12-18fbb24]
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:14
1) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
at org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchCommand(CraftServe
r.java:641) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
at net.minecraft.server.v1_8_R3.PlayerConnection.handleCommand(PlayerCon
nection.java:1162) [spigot.jar:git-Spigot-db6de12-18fbb24]
at net.minecraft.server.v1_8_R3.PlayerConnection.a(PlayerConnection.java
:997) [spigot.jar:git-Spigot-db6de12-18fbb24]
at net.minecraft.server.v1_8_R3.PacketPlayInChat.a(PacketPlayInChat.java
:45) [spigot.jar:git-Spigot-db6de12-18fbb24]
at net.minecraft.server.v1_8_R3.PacketPlayInChat.a(PacketPlayInChat.java
:1) [spigot.jar:git-Spigot-db6de12-18fbb24]
at net.minecraft.server.v1_8_R3.PlayerConnectionUtils$1.run(SourceFile:1
3) [spigot.jar:git-Spigot-db6de12-18fbb24]
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [
?:1.8.0_191]
at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_191]
at net.minecraft.server.v1_8_R3.SystemUtils.a(SourceFile:44) [spigot.jar
:git-Spigot-db6de12-18fbb24]
at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:7
15) [spigot.jar:git-Spigot-db6de12-18fbb24]
at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:3
74) [spigot.jar:git-Spigot-db6de12-18fbb24]
at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:6
54) [spigot.jar:git-Spigot-db6de12-18fbb24]
at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java
:557) [spigot.jar:git-Spigot-db6de12-18fbb24]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_191]
Caused by: com.comphenix.protocol.reflect.FieldAccessException: No field with ty
pe int exists in class PacketPlayOutCustomPayload.
at com.comphenix.protocol.reflect.StructureModifier.writeInternal(Struct
ureModifier.java:363) ~[?:?]
at com.comphenix.protocol.reflect.StructureModifier.write(StructureModif
ier.java:343) ~[?:?]
at me.corner.Main.Main.sendPacket(Main.java:140) ~[?:?]
at me.corner.Main.Main.onCommand(Main.java:199) ~[?:?]
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[spi
got.jar:git-Spigot-db6de12-18fbb24]
... 15 more

EDIT: I fixed it by just doing this: entity.setInvisible(true);
(i didn't know this method)