the only othe sudjestion i have is running 2 computers and run the output of your skype on 1 computer , into the 2nd stream computer then off to the broadcast serv. you could play with multiple soundcards but windows tends to want to only use 1 at a time.
ps: remember to use headphones if you use the stereo input selection while the microphone is unmuted
idealy you could premix your entire broadcast and run it into the stream server line input. (multichanel mixing board mixing: multi efx rack, playback sequencing players, midi, telephone, ect...)