Perhaps I'm confused.
Are you saying the receiver won't accept either digital coax or toslink audio?
Or are you saying the the cable box doesn't offer those as an output?
You don't NEED HDMI for the best satellite has to offer, which is 1080i max. Component will easily handle that unless, of course, your box prevents that.
Virtually every receiver I've seen accepts red/white analog audio inputs for virtually any video input.
You might want to consult your manual for configuration instructions, or check Onkyo's website for one.