I'm trying to create a directory and set accessright on it.

I create the directory like this:

globalDir.CreateSubdirectory("subdirectory");

I then try to set access rights using UnifiedDirectoy.ACL.Add. When I add a AccessControlEntry with the Add method I get this error:

EPiServer.Core.EPiServerException: Cannot modify inherited ACL

Is there some way to create a directory without inheriting the ACL or can I bypass it in some way?