We have successfully used a custom ContentImporter.xsl file during conversion prior to import (using Content Importer). However, the only thing it is modifying is the contents of the .3sish files that contains the metadata that is blended with the corresponding .dita/.ditamap files on the actual import. We can't use ContentImporter.xsl to modify the actual DITA in the .dita/.ditamap files as it appears the content modification needs to be done outside of the content importer.

In terms of scope of capabilities, we understand that ContentImporter.xsl can only be used to generate/prepare metadata, hence the reason it is documented as a subsection of ‘Metadata preparation’ , rather than under the ‘Content conversion’ subsection. https://docs.sdl.com/LiveContent/content/en-US/SDL%20Tridion%20Docs-v1.1.2/GUID-54718636-B182-4226-A504-F1499000F5F7

We would like the ability to point to another XSL to modify the DITA prior to import within Content Importer.