Cannot customize XSL for UBL2.1 message under CMK

Summary:

We are trying to customize the XSL for the standard UBL-2.1-PEPPOL-Invoice-Out-V2 using the new CMK simplified conf. We made a duplicate custom definition and we perform a simple hard coded change in the XSL file. When sending out the invoice we are still seeing the standard XSL verson of the UBL document.

Things we already tried:

• Using a different file name different from the standard one: there is an error "No output from transformation" and no output message file is found
• Creating a message from scratch without duplicating and using the standard file name but with customized contents: the output still shows the standard file name