Can anyone tell me whether the folks here have a formal rule about using copyrighted music in a custom mod?

Can I convert purchased music, stick it in my scenario folder and post it in this forum?:cool:

I think you can't. That would be sharing copyrighted materials and unless the copyright owner gave you the right, it's forbidden.

That's right, it's not allowed here.

With regards to music, there is a certain small amount which can be shared without infringing on copyrights. It is something like 30seconds or something like that. I can't recall precisely, but google should help you find out.