I really thought I'd figured it out with beta 8.
Every mission, DCG will do a check to replace a static plane at any given airfield with another plane matching a type that is being used by a squadron at the base. So if there are no Bf109F0 at the base, they won't appear.
BTW, what mode are you generating these mission in? Campaign (offline) or dogfight or coop? It shouldn't make any difference (I don't think, but maybe there's some code deep in the belly of DCG that I've forgotten about).
Make sure you have no blank lines in your staticplanes.dcg file. (Maybe that's screwing it up.)