Hi Emmanuel,
If the pluralization of collections doesn't suits you, you could just rename those navigators individually in the LLBLGen Designer. The pluralization will run again for new elements, not for the one you just renamed.
If you want to totally disable the pluralization plugin's event, you can do it as well, this is how.
You could even download the SourceCode package from the LLBLGen's Customer section and modify the Singularization/PlurarizationPluglin to your needs (adding additional grammar exceptions, for instance).