private void addVolumes(RunImageConfiguration runConfig, List<String> ret) {
        RunVolumeConfiguration volConfig = runConfig.getVolumeConfiguration();
        if (volConfig != null) {
            List<String> volumeImages = volConfig.getFrom();
            if (volumeImages != null) {
                ret.addAll(volumeImages);
            }
        }
    }
Override externalConfiguration when defined via special property.

@param externalConfiguration Map with alternative config
src/main/java/io/fabric8/maven/docker/config/ImageConfiguration.java