Why not just set them in first place?
[Shadows]
// Generates shadows onto terrain that casts them.
----+ ShadowCasters: On created
----+ System: For each ShadowCasters
-----> ShadowCasters: Spawn shadow on layer 3 (image point 0) (create hierarchy: False)
-----> shadow: Pin Pin to ShadowCasters (image point 0, angle: True, width: No, height: No, Z: False)
-----> shadow: Set color to rgbEx(255, 255, 255)
-----> ShadowCasters: Spawn shadow on layer 3 (image point 1) (create hierarchy: False)
-----> shadow: Pin Pin to ShadowCasters (image point 1, angle: True, width: No, height: No, Z: False)