Localization for DocumentForm

[realhik]

My settings.py has entries for localization:

 LANGUAGE_CODE = 'de'
 USE_L10N = True

When using {{ form.as_p }} in templates for a DocumentForm the decimal seperator is not a comma as expected. Forms are created from a Document by:

class NodeForm(DocumentForm):
    class Meta:
        document = nodeClass

How can I enable localization?