I have added my prefered radio stations as playlists and can start them with the remote by calling the playlist name. That was the cleanest way to do it imo.
I have lines like this in my lircrc :
begin
prog = irexec
button = KEY_1
config = curl -v “localhost:3000/api/v1/commands/?cmd=playplaylist&name=P1”
end
begin
prog = irexec
button = KEY_4
config = curl -v “localhost:3000/api/v1/commands/?cmd=playplaylist&name=P4”
end
I’m pretty shure there is a way to call radio favourites in a similar way but I choose playlists for some reason that I have now forgotten.
I think that maybe you would have to add the playlists manually with an ftp client or something. I think that it was how I did it. Each playlist is in its own file with a format like this:
[{“artist”:“Sveriges Radio P1”,“service”:“webradio”,“title”:“SR P1”,“uri”:“https://sverigesradio.se/topsy/direkt/132-hi-aac.m3u”}]
And I have a feeling that @gvolt was involved in finding out how to do this… 
It would be nice to have this ability to add radio stations to remote buttons directly from the plugin config gui if possible. It’s one of the best features of volumio imo to be able to start the morning radio with the remote.