Guatemala is not a member of The Hague Convention. Therefore, all guatemalan documents to be validated must be authenticated through diplomatic channels.

 

To authenticate a guatemalan or belizen document you must do the following:

 

1) First the original document must be authenticated by  the Ministry of Foreign Affairs of Guatemala.  

2) After that, present it at the Consular Section of the Embassy of Argentine in Guatemala.  The Consular Section will authenticate the signature of the Guatemalan official once the consular fee per document has been paid to this Consulate.

 

Belize is a party to the Hague Convention, therefore you would need to obtain an apostille for your documents.  An "apostille" is a form of authentication issued to documents for use in countries that participate in the Hague Convention of 1961.