[Koha] Item generation for Serial issues

Dear friends I am writing you again for an advice regarding our serials catalog. One of our problems is to generate items for periodicals issues which are holdings themselves. Ian in his response to my first mail mentioned that issues have an option to generate items for themselves at the Subscription level. But we do not know the tool, Can somebody hint us? The second question is about the difficulties with cataloging our newspapers. The fields that are for storing complex serial information, like 853-855, 863-865, 866-868, are absent in koha. What we really need is to display which issues we have and which are missing. Any advises? Does any of you have an experience of cataloging newspapers. Regards, Haik.