Drupal Commerce Checkout Login not working

I'm trying to use the Commerce Checkout Login module (https://www.drupal.org/project/commerce_checkout_login) which adds a login prompt to the Commerce Checkout screen if the email address an anonymous user enters matches a user in the database. My Drupal Commerce site is a slave site in my Bakery environment. I've encountered two problems with it so far:

1. It only recognizes a user if that user has already been copied by Bakery into the slave's user table. It isn't querying the master site.

2. User authentication is failing on the checkout page, even though the correct username and password are being passed into the user_authenticate function. Specifically, this line isn't working:

$uid = user_authenticate($account->name, $form_state['values']['account']['login']['password']);

I used some simple print statements to confirm that the two parameters being passed are correct. I'm guessing that the problem is that Bakery needs to be involved in this authentication process.

Can anyone give me some suggestions for resolving these two problems with the module?

Using:
bakery 7.x-2.0-alpha4+11-dev (2014-May-05)
Commerce Kickstart (commerce_kickstart-7.x-2.19)
drupal 7.32