I sugest add in german OOB in years 1937-November 1939 Selbstschutz non regular formation would be good as german partisants during hipotetical fight in poland and than during September Campaigne. They were armed in typical germans weapons transfered in secret for this organisation from germany kar98k , MG34 LMG and granades. Units should be similar to Volksturm in late war. I know in german OOB is only 20 slots and is hard add new units but you think about this formations. Fights with Selbstschutz in Silesia , Bydgoszcz , Torun in all western poland was a very characteristic for many battles in 1939. This german partisants were know in poland as Fifth column that was a pharaphase of General Francisco Franco who say during spain civil war "My four columns march on Madrid but fifth is in the city
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Some links
http://en.wikipedia.org/wiki/Selbstschutz
http://en.wikipedia.org/wiki/Fifth_column