From BA-MA you could try RM 6/74 which (says Invenio) includes:
»Unterredung Befehlshaber der U-Boote Vizeadmiral Karl Dönitz mit Hermann Göring über Abgabe Kampfgeschwader 40 am 7. Febr. 1941«
= Discussion between Dönitz and Göring re the handover of KG 40 on 7 Feb. 1941.
I haven’t gone into it but if anyone wants to pursue it, it is downloadable.