navigate to /System/Library/SpringboardPlugins and locate the folder titled ‘NowPlayingArtLockscreen.bundle’. Rename this folder to ‘NowPlayingArtLockscreen.bundle.backup’ or something like that.
This works good on iphone 5S and certainly on every idevices.
Go to System/Library/Frameworks/UIKit.framework/ search your lproj folder (in France : French.lproj) and edit the Localizable.string
Search the line »> 3G and if you want the line E
Change the second 3G or E by what you want.