Guys, i solved it, ore atleast this worked for me

 

Go to the Google wallet and sign in with your Google account - http://www.google.com/wallet/

 

Then add the credit Card you want to use (you could delete any old ones inthere also)

 

Now I could by my 10 euro credit and it shows up in my Google voice right after re login to the acount ;-)

 

HandtGuyDK ;-)