[quote:1rfgb9tj]So, it seems you need an actual Mac to upload a C2 Mac build on Steam, because of some permissions problems on the .app.
That's such a stupid requirement.
Then again, that sounds like Steam (and Apple for that matter). Could you pick up a mini and sell it when you're done with it?
option D: Virtualbox
Unfortunately, this isn't 100% straight-forward (okay, or legal), but it is certainly possible. Google "Niresh" and "MacBreaker". Honestly, though, I'd be wary of this option unless you have no other choice.
Anybody you know? Anybody on the forums you'd trust who has a mac?
Hope you are able to sort this out.