Emojis from Android not showing up

I recently got the new iPhone 4S (iOS 5.1.1) and have the Emoji app. I can send Emojis in messages, tweets, etc. and can view Emojis on Twitter as well as from other iPhone users. My boyfriend has an Android powered phone and originally, when I would send Emoji emoticons, he could not see them. After downloading the Handsent app from the Google Market he was then able to send Emojis and view the ones that I sent him. However, when he sends me Emojis they just come up as strange codes like "+h04vC/" and stuff like that. Any idea why he can see mine but I can't see the Emojis that he sends me? In my history with iPhone its usually that other phones are incompatible with our software, but not the other way around. Thanks in advance!