Rule 15.52 indicates that when the Detachment marker is placed in these unoccupied, Allied towns that "Doing so makes the town German." However, the VP rules and Fuel Depot rules do not indicate that it's the ownership of the hex that gives the VP/Fuel. Instead, those rules (17.1 for VP's and 13.52 for Fuel Depots) indicate that when a German unit enters the hex, the German side gains the benefits.
Wasn't sure if placing the Detachment marker was considered "entering" the hex.
Per a post on ConSimWorld, though, John Butterfield has indicated that the VP's and Fuel Depot markers should be awarded when a Detachment is placed in those hexes.
Well, that surprises me. It should be witten in the rules; could you add here the link to ConSimWorld?
The way rules are written suggested me that a "physical unit" was needed