SCP upload flattens subdirectories

If the scp plugin is used with a pattern like
documentation/**, the resulting upload fetches all files in all subdirectories,
but flattens the hierarchy.

This may not be desired behaviour (and in my case isn't). The directory
structure should be preserved while uploading. This effect can't be achieved by
workaround if the directory structure varies.

The specific use case was to upload project documentation. Perhaps there is a
better way?