Andrew asked for per-UDDI-category queries for the OPML lists my little tool creates and here it is:
Optional query parameters:
scheme=<<name of one of the pre-registered categorization schemes in the Microsoft UDDI registry>>
key=<<a key from a category>> (required parameter if scheme is provided)
For the following categorization entry for a service in UDDI (one of the RSS tModels is required in addition to that):
ntis-gov:naics:1997
Information Services and Data Processing Services
514
the proper query is therefore
http://staff.newtelligence.net/playground/clemensv/rssinuddi/rss_in_uddi.aspx?scheme=ntis-gov:naics:1997&key=514