http://www.gentoo.org/doc/en/virt-mail-howto.xml says: "Important: This document uses apache-1.3.x. Apache-2 has been marked stable in portage. However there are still a number of issues with php integration. Until php support in apache-2.0.x is marked stable, this guide will continue to use the 1.3.x version." but now apache-1* is removed portage from several time. I suggest to fix accordingly the document; moreover the chapter 8 talks about apache installation and configuration, i'm not sure if the paths of configuration files are the same of apache-2* layout, it would be better do some check about that :)
*** This bug has been marked as a duplicate of bug 106301 ***
