Need help running PowerShell Script as App Deployment

First off, I would like to thank the dev team for Version 4. However, when trying to run a PowerShell script as the app to be deployed under version 4 the old methods don’t seem to work. I have updated the commands to their new names with little success. Is this still possible in version 4 and if so, could an example be provided. Listed below is the old way for reference. Thanks

Execute-Process -Path “powershell.exe” -Parameters “-Command & { & "$dirFiles\InstallFolder\Install.ps1”; Exit `$LastExitCode }" -Wait

I don’t quite know why you’d fork out to a separate PowerShell process like this… Nonetheless, the replacement command is Start-ADTProcess.