I downloaded DotNetNuke Community Edition via MS Web Platform Installer to my computer running MS Vista. After download completed, installer asks me in Step 2 for DB Admistrator and User name, also Db user name and password. I have VWD2008 and it came with Mssql express 2008 - as part of it. I never setup any passwords- I guess it uses Windows authentication. Usually when I publish ready web site, I just transfer sql express files to the SQL server and manage via SQL Server Management Studio. But it stops me from continuing installation. What should I do?

In Step2:

1. "Choose your database" dropdown list. Gives only 1 option: SQL server.
2. "Create new or use existing db" - i marked "create new"
3. "Database administrator" - it populates with "sa" automatically, so I leave it as is.
4. "db administrator password" - what should I enter? (my original question)
5. "db username" - it populates with "dnnuser" automatically, so I leave it as is
6. "db password" - what should I enter? (my original question)
7. "db server" - it populates with ".\SQLExpress" automatically, so I leave it as is.
8. "db name" - it populates with "DotNetNuke" automatically, so I leave it as is.

When I click NEXT, it says: "db parameter can not be empty", if i try to create password or user name - it does not recognize any. My SQL Express simply uses Windows authentication and there is no passwords or user names. How to proceed with the installation?