The PermissionValue provides access to permission lists associated with folders, content references, PageletCategory objects, or Pagelets.
Note: You cannot add any PermissionValue objects to a collection returned by the CascadedPermissions or CascadedRolePermissions property. You can add values only to the collection returned by the Permissions or RolePermissions property.
PermissionValue objects are instantiated from the following:
A PermissionValue Collection with the First, InsertItem, ItemByName, or Next methods.
A RolePermissionValue Collection with the First, InsertItem, ItemByName, or Next methods.
See Using Security.