Having done this, I decided to attempt to add them to the Custom visuals wizard in the palette so that other user could access them easily, using the information provided here:
I can get an Icon up in the palette and add the CVC to a project but the the required *.min.js file is not copied into the report. If I use either of the built in CVs from the palette (figures or radial progress), the .js files are added to the report correctly.
To convince myself that I had the .json descriptor file right, I copied the built in example folders out of com.jaspersoft.studio.components.customvisualization_6.2.0.final.jar and into a local directory then tried to add them as if they were my own custom visualisations. These local copies behave the same as my own i.e they appeared as Icons in the palette and could be added to a report but when added, they did not copy over the *.min.js or *.css files to the report.
Can anyone shed any light on this, have I missed something?
it is a bug in Jaspersoft Studio, now solved. You can wait for Jaspersoft Studio 6.2.1 or download a snapshot from source forge of a beta release.