Of course you get credited for the kills and the notation of the ship's sinking is in Latitude & Longitude instead of Grid number. Its the same thing in my current campaign I am off the coast of Cairo no grid numbers there but the traffic is insane
You can use the following site to convert Lat and Long to Grid numbers if you wish:
http://www.ubootwaffe.net/quadrant.cgi
It will come in handy because BdU reports convoys by Lat/Long up there so its kind of hard to find it otherwise.
Here is the extended grid coords of the Arctic: AC41 AC42 make for excellent convoy hunting grounds bound for Murmansk.
