If they credit at all, they SHOULD credit automatically. But in some fraction of cases, it doesn't work, and then you have to call them (which might be costly from Germany?) to get the name of the person to fax the receipt (or credit card statement) to them to get it manually added. There is no pattern to this; it just happens at random sometimes. (In each case where I've had it happen at a restaurant I've eaten at several times over time, it only happened for SOME of my visits to that restaurant.)

You do have read the website carefully while logged in, and make sure you know whether that restaurant awards miles every day or only certain days of the week. And also, if you're considering visiting more than once, make sure it says "unlimited visits" in the description, NOT "one visit per month". Those are the two main restrictions (plus not spending more than $600 total in a month at any one restaurant).

Keep in mind that you'll only earn 3 miles per dollar spent on your first 12 dines this year, and after that you'll earn 5+5 (total 10, but posted as 5 normal and 5 bonus) miles per dollar spent. So you may want to do as many cheap dines as you can at the beginning (read other recent threads here about that, about getting cups of coffee or whatever, for example:

http://www.flyertalk.com/forum/showthread.php?t=582883

) to get to the higher earning level as soon as you can.