Using multiple locales in Flash Builder 4.7

Is there a known issue in FB4.7 adding multiple locales in the compiler arguments?

I'm trying:

-locale fr_FR,en_US

...but it looks like FB is trying to find a single locale with the name 'fr_FR,en_US' rather than the pair:

unable to open '/Applications/Adobe Flash Builder 4.7/sdks/4.10.0/frameworks/locale/fr_FR,en_US'

Thanks,

Simon