How can I teach an extension the function: includeonly?

Hello! I use Mediawiki 1.17 with the extension Improved Access Control.
Now I want to use this Code: <accesscontrol>Group</accesscontrol> with a template.
The problem is, the extension don´t understand <includeonly>, which is needed.
How can I teach an extension this function "includeonly" ?
Perhaps with putting a code in a file of the extension? The question is which code in which file?

I love you, if you can help me ;-)