“Good things come to those who wait” or better, to those who act 
I had some discussions with the Vodafone support until I could convince them to release “Dual Stack” for my account. However, using a Vodafone Station and a FritzBox 7490 were still a barrier. As old Unitymedia Customer (NRW) I am not able to use the bridge mode on the Vodafone Station (strange, but a proof that the Vodafone network still makes a difference between legacy Vodafone customers and former Unitymedia customer). So, I invested 200ish € for a FritzBox Cable 6690 and canned the Vodafone Station and the Fritz!Box 7490.
The result:
Summary: It’s possible, but it takes time and money (for the new box)