Hi Herman and welcome onboard!
Unfortunately, there's no public API available at the moment for using the engine from C/C++.
However, the engine supports networking through LuaSocket
which is included with the engine ("Extensions/dll/socket/core.dll" and "Extensions/lua/socket/").
It depends what you want to do exactly but LuaSocket has a good number of features
and I've used it myself for the hiscore system in 8-Bit Commando.
If you plan on making an online multiplayer game it might be a bit more complicated but it should work.