published app for windows phone for free now not able to publish the same app on windows 8 platform

Sir i published a app on windows phone OS 8.0,now i want to publish same app for windows 8 platform.i published windows phone app as a student using Dreamspark key so it was free for me to publish it.I want the same for the windows 8 app too,but when i am entering my Dreamspark verification key it says its not valid,how to get over from this..please help me.....