Hello, @HelderCastro
As you already know, the embedded documentation (Eclipse Menu > Windows > Help Content > Requirement addon section) and specifically the section related to the importer preferences contains the information for the import of custom attributes.
I managed to do the import using your settings file and a sample ReqIf file where I have declared a requirement with your custom attributes Sample_CustomAttributes.reqif (8.5 KB)
I have no access to DOORS so I cannot generate the actual ReqIf file so it may be the reason why it is not working. If you could share a sample file then maybe we can find the problem.
Regards,
Arnaud