In a Windows Installer msi package, created with WIX, I want to execute a custom action (written in c#) that executes a powershell script file that is installed by the installer.

I am using WIX to create a Windows Instaler msi package. One of the files to be installed is a Powershell script that must be executed from the installer to register a scheduled task. When executing the script fails, the UI shows an error dialog, but the installer finishes as if nothing went wrong. But that is not what I want, I want the installer to fail on this and let it roll back all changes.