Thanks for the report. Both biblatex2xml and bib2xml make the assumption that pages can only be numeric entities. I'll release the fix in the upcoming version 4.16.
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A biblatex database file containing
Pages = {S12-S34},
processed with biblatex2xml, bibutils suite version 4.15 date 09/26/12
yields a MODS file with
<detail type="page"><number>12</number></detail>
Thanks for the report. Both biblatex2xml and bib2xml make the assumption that pages can only be numeric entities. I'll release the fix in the upcoming version 4.16.
Version 4.16 fixes the bug regarding non-numeric pages. Please let me know if you run into any more issues. Thanks again.