Hello SMS,
Douglas is right, it is possible.
However, it is a lot of work if you want to get the softtop compartment (with the tonneau cover) retrofitted.
It is easier to put a softtop into the backseat area alone.
www.pagodeinfo.de has a good overview on that - unfortunately (not for me) the article is in German. Currently I cannot access his site, perhaps later again.
Everything else in the other discussion threads. It is nevertheless worth to think about it but on the long run better to buy directly a softtop car - always more valuable. Unless the California Coupé is an outstanding example.
Good luck !
Achim
(Magdeburg, Germany)
