Regression: add file via IMCE pop up window gives 404

With 1.1, I can add a file to a filefield_sources enabled node by opening a pop up window showing IMCE.
The URL is of that window is http://mydomain/ch/imce?filefield=field_file&type=book&app=Datei|url@edit-field-file-0-imce-path

With 1.2, opening that pop up results in a 404, on URL: http://mydomain/ch/filefield/imce/book/field_file?app=Datei|url@edit-field-file-0-imce-path

Obviously, the URL naming scheme has changed, probably due to http://drupal.org/node/830696

How can this be fixed? I just need to update because of the security issue...

Thanks,
Stephan