Hello,
Thank you for contacting Steam Support.
Our records indicate that your purchase was declined due to your current IP address differing from your billing information.
We have removed the lock on your account - you will now be able to complete additional purchases.
Additionally, you will need to use the following link through either Internet Explorer or Firefox to complete your transaction.
http://store.steampowered.com/?cc=it
Please bookmark this link for continued purchasing while you are traveling out of your native country.