Brake Electric Antilock problems of the 2006 Volvo S60

Car type: Volvo S60r model year 2006 (euro spec. ) manual transmission. Technically near identical with Volvo S60r sold in us market, except for lights and speedometer. Temporary complete loss of brake power going uphill at moderate speed (+/- 30mph), when depressing clutch and attempting to brake. Occurred a number of times, under similar conditions. Under this condition, the braking distance becomes very very long. When it happens, it is accompanied by a sort of spring release noise that seems to come from the rear haldex coupling. Would lead to accident in dense traffic. There seems to be a software interaction problem between the computer that controls the haldex awd system and the abs system. Requires immediate attention as this intermittent failure can cause severe car crashes at intersections and pedestrian crossings. Volvo is unable to find the problem as computer stores no fault codes.