The Multisite Launcher setting goes through the Radio Assist setup and is based on the remote databases management.
Open the RadioAssist setup.
Connect with your login and password.
Il the "Database" tab click on 
The following windows opens :
For each database used with the Multisite Launcher, select "YES" in the "Launchable" column.
Click on 
The database(s) selected will be shown in the list when launching Radio Assist.