Some confussion occurs with language code and keyboard model. Catalans of Spain use computers with spanish keyboard (ca_ES keyboard), but catalans of France use computers with french keyboard (ca_FR keyboard), anyway, the language is the same: "ca", and this is OK. Thanks by correcting it and by the interest.
About the dictionaries, I understand the policy, and I agree with theducks about including a link on the dicctionary preferences page. The ones he proposed results with an .ocx file and, surely, will require additional instructions. But, at least, a link ponting to the User Guide section about how to get and install other dicctionaries will be great, I think.
Greetings from Barcelona.