I think they started to focus it on Lua, but you just add a C++ script to the project either way. I can't remember how, I don't really use this engine much at the moment.
It says on the following link that visual studio 2013 is supported, is the pro version of 2013 supported though?
http://www.leadwerks.com/werkspace/page/documentation/_/user-guide/getting-started/compiling-for-windows-r624