When you say "hard top" do you mean that it's all one piece, or that you have a removable hard top, and now want the soft-top?
If your jeep is all one piece, it can't be done without crazy expensive custom body work.
if you have a removable hard top, you can get a soft-top kit from someplace like JC Whitney. You don't have to get 1/2 doors if you don't want to. They look better, but I used to have to brush snow drifts off my seats when I went to my car in the morning in Wisconsin winters.