translatable strings in module-templates not found

[cryu]

I have a custom Login-Handler (overridden from userbase) which uses a custom template. The template is located in templates/_m/userbase/login.html. Running make for finding translatable strings does not find translatable strings in this template. If this template contains a string which has already been translated in a .mo file the translation is shown.

String to be found:

<h2>{{_("Please log in")}}</h2>