No answer, I solved it at the moment by overriding the pageprovider. But I dont want to solve it this way. The problem is that the PageProvider requires EpiServer Enterprise. There must be another way to solve this?

  public class OverridedLocalPageProvider : LocalPageProvider
    {
        public override EPiServer.Core.PageReference Copy(EPiServer.Core.PageReference pageLink, EPiServer.Core.PageReference destinationLink, bool publishOnDestination, bool allowThreading)
        {
            return base.Copy(pageLink, destinationLink, false, true);
        }

    }

And then added the following to episerver.config
  <pageProvider>
    <providers>
      <add name="default"
           type="Saab.EpiServer.OverridedLocalPageProvider, Saab.EpiServer"
           capabilities="Create,Edit,Delete,Move,Copy,MultiLanguage,Security,Search,PageFolder" />
    </providers>
  </pageProvider>

If it's only done 4 times a year I would probably do a Action Window plugin where you choose source and destination and then execute the code above. Seems a bit drastic to "create" your own pageprovider for that purpose.

Another approach could be to attach an event to publishing-page, not sure how to check if you're copying a page, but I guess you can somehow.