Created Unassigned: Mount instead of create content DB [20843]

When you create a new Web Application via the UI, if you specify a database that already exists it will mount/upgrade the database. If you try this same approach with AutoSPInstaller, you get this error...

- Creating Web App "WebApp"
New-SPWebApplication : This content database requires upgrade and could not be attached in this operation. Use either
the [stsadm -o addcontentdb] command or [Mount-SPContentDatabase] cmdlet instead.
At \\Wayspdbdev02\sp\AutoSPInstaller\AutoSPInstallerFunctions.ps1:2524 char:9

Could this be accomplished in ASPI?