Hey Doug, Joe and all, Many thanks for two helpful replies. The apache-based solution indeed seems satisfactory. Now the next question is: how to generate the right URLs ? Assume an existing MARC record. Suppose a librarian wants to attach an additional file to this record. A form is presented to her where she chooses the right format from a format list and types in the file to be attached to the record. Then the MARC record has to be updated with one more URL (e.g. 856$u). What in Koha would you guys modify to make such a procedure work ? Many thanks for your help ! Sébastien.