Sub-libaries in a package and use-package ?

[David Masterson]

The 'async' package has 2 extra libraries (dired-async &
smtpmail-async). I'm trying to figure out how to set these up with
use-package, The documentation for use-package in chapter 3.1 says:

----
But the ‘foo’ package might also contain a library named ‘foo-extra.el’.
If that library is not loaded automatically, you will need a separate
‘use-package’ declaration to make sure that it is.
----

It doesn't say anything else about this (CMIIAW), but this suggests to
me that the following should work:

(use-package async
  :config (async-bytecomp-package-mode 1)
  )
(use-package dired-async
  :config (dired-async-mode 1)
  )
(use-package smtpmail-async
  :config (setq message-send-mail-function 'aync-smtpmail-send-it)
  )

But the following error when I start Emacs:

Error (use-package): Failed to install dired-async: Package
  ‘dired-async-’ is unavailable 
Error (use-package): Failed to install smtpmail-async: Package
  ‘smtpmail-async-’ is unavailable 

This suggests that use-package can't find the *package* when all it
should be doing is picking up the library in async which already
established the load-path.

What am I missing?

-- 
David Masterson