Marc,
You should be able to instruct the archive to move the series to a destination of your choice. Try something like this:
destination = 'MY_LOCAL_DICOM_STORAGE_WHICH_THE_ARCHIVE_IS_AWARE_OF'
series = node.find_series('0020,000E' => series_uid)
series.each do |s|
images = node.find_images('0020,000D' => s['0020,000D'], '0020,000E' => s['0020,000E'])
images.each do |image|
node.move_image(destination, '0008,0018' => image['0008,0018'], '0020,000D' => image['0020,000D'], '0020,000E' => image['0020,000E'])
end
end
end