Pipeline for processing TEI to IDML. In this step a recursive listing of all files in the images directory is done. The results are needed later to determine whether cover or advertising pictures are avaiable. If the directory doesn't exist the pipeline fails, therefore this try-catch is implemented. An images directory could also be created via Makefile target mkdirs. Transpect step to convert XML to IDML. Configurations for this customer: https://subversion.le-tex.de/customers/gfn/transpect/a9s/common/xml2idml/ Option validate-idml: no