Problems configuring Reporting Service (Express Edt.)

Hello there.
First: The problems have their orinin in ExpressEdt.Installation of RS.
The DefaultInstallation did not SetUp the ReportingServices, just
installed the files. So I had to configure the ReportingServices on my
own. I used the "Reporting Services Configuration Manager".
Now I've got some problems configuring the reporting services. First
problems are the virtual directories.
I've tried some different users for authentification. I used a local
user with lower rights, an admin-user, Network Service and
IUSR_MachineName for directory security. Tried to use
WindowsAuthentification and AnonymousAcces.
The AppPool-Identity runs with NeworkService rights.
When I browse the page i get an "You are not authorized to view this
page..."-error.
The mentioned users have rights on the local folders and are in
IIS_WPG-Group.
Whats the problem here?
Second thing I have to tell is that in "RS Config Manager" the
"Initialization"-tab has a (X), so i cant get into this program-part.
Please help me...
tobiHello There.
I found out the problem is caused by the website where the virtual
directories are in.
For publishing the website I put an IP-adress in and made some host
header-entries. After deleting the host headers ReportManager und
ReportServer are working fine.
Whats the problem using RS and HostHeaders?
How do I config them right?
I get the error: "HTTP Error 401.1 - Unauthorized: Access is denied due
to invalid credentials"
Credentials AppPool: "Network Service"
Credential WebSite: Windows Auth.
Credential VirtDirect.: Windows Auth.
As Credential i us a local user. This user is in Adminstrator group.
Thanks in advance, Tobisql