If key component exists on same page as component, use ajax to load the publications.

Here is a patch which extends the above stock Drupal AJAX solution to incorporate some feedback from actual users:

• Disable the submit button until the webform_publications component has been loaded via AJAX, thereby avoiding form validation error messages about missing components.
• Trigger AJAX as early as a valid Postal Code has been typed in, not only after the input element lost focus. ("You have to click *outside* the postal code field for some newspapers to show up." ... was something which was really hard to explain to casual users.)

Make postal code validation case-insensitive.