In the 3D GameStudio specification on the website it's never said that
you may script C++.

Quote:

---

Lite-C is a lightweight version of C/C++, the language used for commercial games programming. But unlike C++, it's extremely easy to learn and the best way to get introduced into 'real' programming. Anything that's scary to a beginner, like memory and pointer handling, is automatically managed in lite-C.

---

Quote:

---

If you prefer to program in 'real' C++, Delphi or other languages, you can implement Gamestudio's engine into your own programs using the engine SDK. You can even continue to use lite-C as a scripting language; lite-C functions and variables can be called from your program and vice versa.

---

This means that you may use the engine (as a dll) in your own C++ code or
write your own C++ plugins so they can be used by the engine and lite-C.
Not that you can script in C++.

Kindly
~Roland