Promoted to "Obersturmführer" on arrival, his application for transfer to Finland was granted following the discovery that the volunteers would be deployed in the Ukraine. He then served with the Finnish Volunteer Battalion of the Waffen-SS of the 5th SS Panzer Division Wiking for several weeks in 1941. Wrang subsequently joined the Swedish Volunteer Battalion on the Hanko Front during the Continuation War and saw action in the Battle of Hanko in 1941. One who opposed his discharge was SS recruitment manager Gottlob Berger, who felt the decision should be challenged as Wrang could be useful for "future work" in Sweden centering on recruitment. In 1941, he was promoted to lieutenant in the Finnish Army. Returning home following his service, he rejoined the Swedish Army and was promoted to lieutenant there as well.