Gpg4win for Outlook 2007 with 2010 & 2013

Tested Gpg4win on all 3 version of outlook. Namely as the subject state, all work pretty smoothly except… when using 2010 & 2013 to send an encrypted message to 2007, and trying to decrypt the message… nothing happens even after clicking decrypt button. Why is this so? But when using outlook 2007 to sent to outlook 2007, everything else works just fine… Is there anything that I’ve done wrong in this case?