Here is how I would do it:
1. Get "Poof!" (in Cydia) to hide the original stocks icon,
2. If you have Winterboard(Cydia), don't modify iSteamy, but SSH or iFunBox into "/Library/Themes" and make a new folder, name it whatever you want, just remember what you named it! Put a new folder in it, "Bundles", and in that put a new folder named the same as iSteamy's app folder. Copy the Info.plist and icon.png here, modify away!
And now you have a stocks app no one would ever think to look in
(I use Winterboard for this stuff so i don't have to backup the whole app, just copy what I want to change, and that way If I manage to somehow screw up, mobilesubstrate will let me fix the problem)