There is another method which I've found successful:
You can put the sign underground, with a redstone wire leading to a protected room. You can then hook up a lever to this, which will remotely toggle the gate.
Another method is to use a redstone wire to a hidden CraftBook lever (details can be supplied) so a right-click on an innocent-looking block will trigger the gate.
Let me know ingame if you require assistance with either of these, I'd be glad to help you out <object class="emojione" data="
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