Hi Christophe,
In the 'Mediation' Perspective (Route Builder):
1) add your config file to to 'Resource' node (right mouse click on the resources allows you to import it)
2) add this resource to your route (use also right mouse click on you route to do this)
3) use classpath:// {your resource name} to refer this resource.
Haven't really tried it but this is the way it works for nearly all components as long as they support to get the resource from the classpath at runtime (which is the case for all / most camel components.
When you export or publish your route the flatpack config file will automatically added by our studio to export (kar/jar files) and is accecible for the component by this using the classpath:// (instead of an external file file:// )
HTH,
Dietmar