Can't copy cloak in editor

[PJackson]

I was trying to create a custom cloak today. It should combine the functions of a Cloak of the Hedge Wizard (abduration) and a Cloak of Resistance +2. I expected it to be quick to do buy copying the more complicated one and adding the resistance bonus. However I am not allowed to copy the Cloak of the Hedge Wizard.

Is there a way to get permission to copy it?
Otherwise I suppose I will have to add each of the functions myself.