XMLP Report Developer Role
In order to develop XML publisher reports, make sure that you have the XMLP Report Developer role. If you don't have this role you won't be able to change the data source type from PS Query when adding a new report definition.
The report definition search page is based on the report category ID and author ID. So if you can't see any reports it may be because your operator ID is not an author ID or you do not have the appropriate author ID role.
Here's a query to check:
select * from PSXPRPTCATAUTH
You can also change this through:
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