i don't know if mine is the exact same as yours, but are your posts deeper in the inside? mine require a separate, white plastic washer to sit on top of the liquid/gas tube. mine has a plastic gas tube, but i plan to replace it with a stainless one. i don't think the lids are interchangeable as the shape is different, but the seals sold for normal ones seem to work fine.
here's a short thread i just posted dealing with the same thing. there is a link with parts for these kegs.