I think the reason for the mold has more to do with humidity than heat. I reallt doubt that turning the insulation around will make a difference. However, there is foil backed insulation which is more common in commercial applications which must be turned out rather than in. It works by blocking the radiant heat form entering the building. To reduce mold and mildew you must reduce the humidity with good ventilation. Perhaps even employ the use of dehumidifiers.