Try leaving your sound device option set to Auto-Switch (Windows Default) then change your default sound card to your preferred one by clicking the speaker icon in your system tray (notification area) then click the little arrow to switch between different audio devices.
If the old FF7Config.exe is not properly detecting your sound card, most likely similar code is used in the game so therefore will also not work. 7th Heaven is obviously more modern in that regard and can do playback tests correctly with your card, but it can't force the game code to work with it. If you follow my steps above, you're sort of telling the game to just let the OS handle it and it may work that way (which is why it is the default option in 7H). If still no go, try updating your sound card drivers direct from the manufacturer of the chipset's web site. Windows' built-in audio drivers are notoriously garbage. If your sound card functions with some kind of proprietary non-standard or uncommon voodoo via some added on driver bells and whistles, see if you can disable them or put the card in some kind of legacy/compatibility mode via the driver software and try again.