Same problem here. Installed Homebrew Channel 1.0.8 (latest) and IOS58 as well as WiiMC Channel Installer 1.3 and WiiMC 1.0.7. No HDD detected via channel. Strange thing is, I still get no HDD through Homebrew Channel.
Played around a bit, uninstalled IOS202 and uninstalled the WiiMC channel and installed WiiMC Channel Installer 1.2 (older version). Unplugged and replugged my HDD and now my HDD is displayed via the WiiMC Channel and this is with WiiMC 1.0.7. 1.0.7 still seems a little buggy, freezing and the HDD goes missing for a bit but apart from that it is working with my HDD now.
Maybe that’s something to try for now. Use WiiMC Channel Installer 1.2 with WiiMC 1.0.7.