Big World Set Up Only Usable with BG Trilogy?

So downloaded BWS, but then the only option offered is "BG2 trilogy" for which game to link it to.
Now I found a walkthrough on YT which clearly shows the demonstator selecting BG2 (standalone?), but there's no option for that.
Also my download is the 1.6 version, I simply don't like the later versions.
Sorry if my language is so untechnical, but basic question is, what now? Am I right in thinking you have to have the trilogy now?
0