Mistake in the BizTalk Server 2006 Installation Guide for Windows XP.

I just installed BizTalk Server 2006 on my laptop, a Windows XP machine.
Microsoft provides installation guides for BizTalk 2006 for every Windows version officially supported by BizTalk 2006, see BizTalk Server 2006 Installation and Upgrade Guides.
So, I strictly followed the installation guide provided for Windows XP (BizTalk Server 2006 Installation Guide – Windows XP.doc) and I could not have one of the post-installation tasks to work (Post-Installation Requirements, p.49 of the document):

“Add the HWS Web Service user to the IIS_WPG and STS_WPG Windows groups.”

My machine does not have any user named “HWS Web Service”, neither an IIS_WPG nor a STS_WPG Windows user group.

I believe that this post-installation task should not be part of the Installation Guide for Windows XP.
Indeed, I did some research and came with the following thoughts:

1. IIS_WPG is a Windows user group created when installing IIS on Windows Server 2003. Windows Server 2003 runs IIS 6.0 and has the concept of Application Pool. Each Application Pool runs in its own Worker Process (w3wp.exe). The Worker Process must run with a Windows user that belongs to the IIS_WPG as the group provides the minimum set of privileges and permissions required to start and run a worker process.
Windows XP runs IIS 5.1 which does not have the concept of Application Pool – it’s new with IIS 6.0, so, there is no Windows user group needed for it.

2. STS_WPG is a Windows user group related to SharePoint Portal Server. As SharePoint can’t be installed on a Windows XP machine, that user group can’t possibly exists on Windows XP.

So it seems that this post-installation task is needed to give the HWS Web Service Windows user the rights to run some SharePoint component and to run its own IIS Worker Process on Windows Server 2003.

To conclude, I assume that this post-installation task is just a mistake in the installation guide document. It is something that you have to do on Windows Server 2003 but not on Windows XP.