[toLua] Putting a non-standard global?

[L-28C <kixdemp@...>]

Hello everyone!

Look, this works:

lua_pushstring(Script, filesDir);
lua_setglobal(Script, "FilesDirectory");

But this doesn't:

tolua_pushusertype(Script, WalkLayer, "Image");
lua_setglobal(Script, "WalkLayer");

I assumed tolua_pushusertype(...) was the toLua equivalent for 
lua_push*(...), but it seems I was wrong...

What's the right way to push a global of type 'Image' (binded to the 
script, of course)?

Thanks! ;-)