Zbuffer disabled and picking

i’m rendering an object in 2 different styles depending if it is hidden or not.
First, i render hidden parts. This is done by using the zbuffer function GREATER and disabling Zbuffer writing.
Then, i render visible part normaly.

That’s ok, but my hidden parts are not pickable. Is there a way, during the rendering of the hidden parts to force pushing names on the namestack (even if zbuffer writing is off) ?
Or i am forced to do a third pass, without displaying anything (invisible for example), but with ALWAYS writing in the zbuffer ? And, what’s the best solution to achieve that ? (full transparency or is there a way to force to write zbuffer only ?)