How to add a cordova resource file (custom ringtone)

Hi all,

How to add a custom ringtone to a Meteor Cordova iOS app?
I’m using the cordova-call plugin, to take advantage of the iOS CallKit framework.
In cordova-build-override/ I’ve added the ringtone file and in mobile-config.js used App.appendToConfig(element) to declare a resource-file, as is described in the package readme.
But get an error when meteor run ios-device:

=> Errors executing Cordova commands:         
                                              
   While adding platform iOS to Cordova project:
   Error: Source path does not exist: all_that_she_wants_i.caf
(...)

Is there any straightforward way to do this in Meteor?

Thanks