How to configure Com+ .net Assembly called from classic ASP to run under AppPool User

Question

I have a very specific scenario: A classic ASP application is running a .Net Assembly through COM+. It's working, but I'm having problems regarding which user the DLL is running under.

In my staging server, both w3wp.exe process and the .net DLL are running under AppPool user : IIS AppPool\AppPoolName. But in the production server, w3wp.exe is running under AppPool user, while the .net DLL is running under NT Authority. I need it to run under AppPool user so I can configure permissions to a folder the DLL needs to write to.

I discover the user the DLL is running under calling Environment.UserName in C# code.

Some things I've already tried and checked:

• My app is running on a custom web site under iis (Not DEfaultWebSite), with its bindings properly configured to http 80.
• The web site is running on a exclusive AppPool.
• The AppPool is configured to Integrated pipeline
• The AppPool is configured to use Identity: ApplicationPoolIdentity
• IIS \ MyWebSite \ ASP \ ComPlus Properties, the settings on production server are the same than staging server.
• In Task Manager, w3wp.exe process is running under AppPool user.