you should tell Seam that is should include your own bundle to its default.
The most simple one is using the name
message.properties and its language specific message_XX.prioprties
and place it in the class path. The other one is adding let Seam handle the stuff. The defined resources are normally added to the default set by Seam and there is also the option to add a specific bundle by configuring it in componenst.xml.
In your case using the standard Seam definition should work.