Hi @freyma,
These resources should not be imported into Specify directly. These XML files are not considered “form sets” as they are not valid as a form definition.
In this case, you will need to replace the files in your Specify 6 installation directory (on a Mac, that would be /Applications/Specify/config by default) with the ones I provided above. These are the files Specify looks at to determine which fields are usable in the WorkBench.
You should save a backup copy of the originals somewhere on your computer just in case you have any trouble. Let me know if you still don’t see it then!