Losing the lang when click on personnal link

Hi Everybody !

I just installed QTranslate on my website.
It works correctly. I can switch language thanks to the widget.

When I click on a link menu, it works good.

But, when I submit a personnal form, or when I go on a personnal link (not linked with the blog), I lose the lang…

(I’m using ?lang= method)

Help me please !

http://wordpress.org/extend/plugins/qtranslate/