Digitar 24 and Sinarback 75LV. And the camera was??? What was the set up in the back? Was the camera/back connected to computer or did you shoot on to the CF card?
The white shading file of Sinarback 75LV is in the back - when shooting on the CF card you can make a white (grey) balance manually. Only if working with computer, you can make additionaly white shading for the lens or for the scene.
Master modus - you trigger from camera and the camera triggers the back.
Slave modus - you trigger the back (need a sinarback trigger) or you trigger from computer when conected and back triggers the camera.
When using MF cameras like Mamiya AFD..., Hasselblad H1/2, Contax etc. and you are conected to the software (Captureshop) in most cases / configurations / you can choose on the fly to trigger the camera or to trigger from computer.
I don´t know if this will help you but I hope you´ll find a way to take pictures without magenta and green hue.