Problem with syntax switch (1.0 to 2.0) and internationalization

If a page exists in different languages, and if I switch from syntax 1.0 to syntax 2.0 in a version that is not the "Default language" one, the page version is still in syntax 1.0 (old Wysiwyg, old syntax etc).

Example :
I create a page, English is my default language.
I translate this page in French.
I switch this French version in syntax 2.0
The syntax 2.0 is not recognized even if my Document Information panel says that I'm in syntax 2