Hello Christian,
Although I'm also very interested in this subject, I can't really help you with precise information. The only time that I've seen sombody mentioning a KGr. Kroatien is here
http://mysite.wanadoo-members.co.uk/...ses/losses.xml - under no.11.
The loss is from 1943, so perhaps a little bit to early?
regards,
Tomislav