Doesn't work with Commerce checkout user forms

I installed the module today. It works well for the standard Drupal user login form, but it does not work for the user login and register form shown in the Commerce checkout process. How can I make this work?

This is what I have in my settings for the module:

user_login_form,user_register_form,commerce-checkout-flow-multistep-default

I also tried it with underscores, and that also did not work:

user_login_form,user_register_form,commerce_checkout_flow_multistep_default

Thanks!