PEAK XOOPS - D3 - 3rd module plugins

With duplicatable modules, "plugin modules" like sitemap or waiting find module side plugins like ...
XOOPS_ROOT_PATH/modules/(dirname)/include/sitemap.plugin.php
XOOPS_ROOT_PATH/modules/(dirname)/include/waiting.plugin.php

For D3 module, sitemap is modified like ...

First, sitemap searches a plugin under ROOT
XOOPS_ROOT_PATH/modules/(dirname)/include/sitemap.plugin.php
Second, sitemap searches a plugin under TRUST
XOOPS_TRUST_PATH/modules/(trustdirname)/include/sitemap.plugin.php

In sitemap.plugin.php under TRUST, write a function like this.

function b_sitemap_d3forum( $mydirname )
{
  ...
}