can’t help too much with your setup, but i can tell you that i went through a similar issue 2 weeks ago. I had to capture analog video and audio into the box. I ran the audio through my mixer, and out to my extreme 3d card. Prefs were set to analog audio…just like yours. Premiere set to capture from blackmagic, not dv or hdv. I could monitor the video coming into the box, but not the audio…so i assumed it wasn’t going in, but upon playback of my captured clip, it was there. I posted a question about this on this forum. (monitor audio) but got no responses. I don’t think Premiere will show us the audio as an input source…only playback from timeline.
You are saying you’ve tried to play back your capture, and there is nothing there? Maybe feed it a true video source as well (vhs or dvd…anything with an actual signal)
Glenn