Make field "Other number" integer type

I need biblio to store a list of publications from an organization. The publications can be articles published in scientific journals as well as annual reports and other internal publications. Each publication is assigned a number in the publication series of the organization. However, I have not found a good field in biblio where I can store this publication number as an integer.

The reason I want to store it as an integer is that I want to use Views module to make a list of publications included in the publication series. The list should be sorted on the publication series number. The problem is that neither the field "Other number" or any of the custom fields are stored as integer in the database. This mess up the sorting of fields, since they are sorted as text rather than integers. There are hundreds of entries in the publication series.

My suggestion is to add a new custom integer field to biblio, or to change an existing field like "Other number".

Of course I could make this publication list as a custom node type using CCK, but then I would miss out on author handling and other useful features of biblio.