Another option would be to complete the vector with only the red and blue portions. Once completed, create a copy of that vector and insert a rectangle shape in the exact dimensions as the copied vector right behind it. Once you have them perfectly aligned, select both objects and use the "Punch Out" operation (right-click when both objects are selected > Shaping > Punch Out). You'll be left with the area that would have been the white color. Then combine that with the Red and Blue vector and you should be set.
Hopefully, that helps!
Good luck, -Russ