Hi Erik,
I've successfully registered IBGE as a GeoNetwork CSW 2.0.2 APISO resource, but to be able to harvest metadata from this catalog I've done some changes in iso-19115-definition.xml file: removing the xsd reference and setting the validation required to false on several parameters. Apparently theirs custom profile implementation, MGB, has some issues when validating with standard ISO profile.
Implementing MGB custom profile and validating IBGE harvested metadata with it should fix this.
Best regards,
Carlos.