I think injection is a great project, really useful and I think the same applies for me, i'd love to contribute to this marvelous software. I've compiled latest avaiable sources, on sourceforge (305) but are not useful for latest clients (i use 188.8.131.52)
I'd be happy too to collaborate with yoko and you to improve Injection.
Anyway, you could find a script.dll version with INCLUDE feature, just what you were looking for. It's a bit bugged, but almost works for standard use.
I'd also love those source code, to correct the bug
Thank you to everyone!