Hi Javier,
THIS IS NOT AN OFFICIAL SOLUTION
But if you notice, an .ais file is almost identical to an .aia project, except it only contains the screen files.
So I think you could simply download the full .aia project and, using 7zip or something similar, delete from the src folder the screen files you don’t need.
(also remove the assets folder)
After making these changes, you just change the file extension from .aia to .ais.
Try it, but as a first and most important step, make a backup of the original project because I’m not able to run deeper tests right now.