Translation file is wrong embed in the installer binary

I have a config.xml that tries to load a translation file like the following way:

<Translations>
    <Translation>pt_br.qm</Translation>
</Translations>

When I run the generated installer with -v option the in-binary resources tree is loaded as follows:

:/metadata/installer-config/pt_br_qm.qm

I checked the code and this file is never loaded since it will try to load pt_br.qm directly.

If I change the config.xml to the following:

<Translations>
    <Translation>pt_br</Translation>
</Translations>

The pt_br.qm file is never copied to the binary since the binarycreator isn't able to find a pt_br file.