code: public Map<String, StringListAttribute> getCustomAttributes() {
          Map<String, StringListAttribute> rslt =
                  new HashMap<String, StringListAttribute>(attributes);
          for (Preference p : accountEditAttributes) {
              rslt.remove(p.getName());
          }
          return Collections.unmodifiableMap(rslt);
      }
docs: Provides a collection of the user's attributes that are 'custom' in the sense that they are
  not listed in the <code>accountEditAttributes</code> bean in userContext. This collection is
  a subset of those that would be returned by the {@link getAttributes} method. This collection
  is <b>READ ONLY</b>.
  
  @return The user's attributes that are not listed in <code>accountEditAttributes</code>