Vault 2.0.1 install on Domain Controller

Before I go through all the steps listed on the support page for 
creating an ASPNET account, assigning directory permissions, etc.,
could someone explain why this is all necessary when I don't 
recall doing any of this for Vault 1.1 (when I was evaluating it)?

I presume you guys would concur with MS that using the SYSTEM
account in machine.config is the wrong way to go. Rather, creating
an ASPNET account as a User, assigning directory permissions, etc.
is better?

And is it true, as mentioned in one of your forums, that this is
really an installer error and that it should install just fine
under the first radio button choice when choosing the ISS Process
Model? Will this be fixed, or is there really no way around it?

Thanks.

As an aside...

I found it interesting in reading up on this (after my install
failed), that the ASP.NET framework doesn't run by default under
a Windows 2003 Server? I had installed Visual Studio .NET on 
there awhile ago and had run through some web app tutorials, and
they seemed to run fine. But I did notice that there is no 
aspnet_wp.exe that shows up in Task Manager, even when running a
web app. Does it use a different name? How is the web app working
if it's not running?