saveXML does not apply XSL transform

I have an XSL that I want to use to populate a 2d barcode. I've set the data connection like so:

However, when I call

  this.rawValue = xfa.record.saveXML();

it does not apply the XSL transform. What do I need to do to force the transform? If I do a Export Data operation from Acrobat, the resulting XML file is transformed, so I know my transform works.