Custom RSS feed for specific author and post type

Hi all,

I would like to offer visitors a specific feed, based on the author AND the custom post type.

I know I can display a feed based on the author (e.g. /author/stef/feed/) or a post type (e.g. /seminars/feed/); but in this case I would like to combine the two, so all posts for this custom post type placed by a specific author are displayed (“seminars” posted by “Stef”).

This does not need to be a dynamic solution, a single url/solution for this specific case would do.

Does anyone know how to accomplish this?