Since the release of android 4.1.2 a change has been made and your carrier will recognize if it's tethering or normal internet traffic and if tethering it's not included in your plan they'll apply addictional rates. After a month of google research i found a thread on the official android support forum where a user posted the solution. Free Tethering Fix will help you applying this fix automatically at every boot[NOT WORKING ATM, I'LL FIX IN THE NEXT RELEASE], so you'll not be charged of other fees for the tethering traffic.
Link to block paid tethering from vodafone website: http://goo.gl/ks68tJ
EDIT: NOT WORKING ON ANDROID 4.4 KITKAT
I'm working in a new app that let you unlock tethering on 4.4, will ne out in some days :P
*added a function to check if terminal is rooted
*new toast to let you know the status of the app
*added StartApp SDK
*updated StartApp SDK
*Removed every type of ads, the application is now AdFree
*Added PayPal donation button
*Reduced a lot the application size
Fixed a problem on layout that was causing fc on low dpi devices.
THE APP IS NOW FULLY WORKING FOR EVERYONE!