Nico,
There are several photos of the machines of this unit. They were attached as Platzschutzstaffel for JV 44, and if you search for "Papagei Staffel" quite a lot of information is out there. I found it interesting that the leader of the Fw 190 unit, Lt. Sachsenberg, is supposed to have said that he trusted any airplane with a propeller on it-- but not the jets!
Yes, the red/white undersides were to distinguish them to their local Flak protection. The operation of this unit was to take off and orbit at 1,000 feet looking for enemy fighters when the Me 262s were in the vicinity of the field or in the landing pattern.
This Staffel had four (possibly five) machines, a mix of D-9 and D-11. The airplane I built has been suspected of being Fw 190V-58, one of the prototype D-11s, according to research info I've found. This is the likely reason for the 58 under the red 4 on the fuselage. Each airplane had personal markings, so unusual at this late period.