You can do this with Studio One 3.5 and Windows Audio.
ASIO does not support more than one device in a single system at time unless it's part of the product architecture (which is usually from the same manufacturer). On OSX you can set up an Aggregate Audio device in Audio MIDI Setup. Since Windows does not work this way you must use Windows Audio.
Most Windows based DAWs that use WDM Audio will have separate input and output selections. In Studio One this is a little different. Windows Audio must first be selected. Then click the Control Panel Button and you'll be presented with options for selecting your Input and Output devices.
