Nobody can find the source code for Icewind Dale II

The people who make enhanced editions of old role-playing games like Baldur's Gate and Planescape: Torment want to do the same thing for Icewind Dale II. There's just one problem: nobody knows where to find the code.It's hard to believe that things like this happen - Icewind Dale II was released about 15 years ago, developed and published by big, popular companies. You'd think the source code would be properly protected and stored.