Hi Sturle, thanks for your reply. This is the first time something like this happens to me, I never had problems with MtGox before.
I understand there is nothing I can do, except checking now and then http://skanner.net/MtGox/mtgox_tx.php

When the present transaction will be canceled, it will disappear from http://skanner.net/MtGox/mtgox_tx.php I assume, is that correct?
The new transaction will also broadcast to the blockchain with a different tx number I assume. But what if that still doesn't go right? Then in that case I can't follow it anymore, can I?

Such a bad timing! Also, I don't get why the http://skanner.net/MtGox/mtgox_tx.php reports an amount of more than 12 BTC, my withdrawal was only about 1.2 BTC... I guess I'm a real noob when it comes to transactions gone wrong!