I have never needed to get the scripts executed as the logged on user. I tend to run apache with an account that has the correct permissions for what I require. If I need the scripts to access more resources, I then grant it to the account.
You might be able to use SUSExec but I have never used it, and I believe that it can cause security issues.
Alistair
Comment on Re^2: NT Authentication - CGI as valid NT domain account