CiviMail from contact search results - forgets details when resuming a save-and-continue-later mailing

In 2.2 beta 4 for Joomla 1.5.7 when I resume a mailing to the results of a contact search, that has been saved-and-continued-later, some details are forgotten. I can reproduce this in the Drupal 2.2 demo.

The details forgotten are ...

• Contacts from the contact search
• Base Group
• From Email Address

This is what I did ...

• Create a group called Empty with no contacts (this will be the base group for the mailing)
• Ensure there is a non-default From Email Address (this will be the from-email-address for the mailing)
• Search for contacts, so that only one result is listed
• Select the Mass Mail action
• Make the Empty group the base group
• Set the From Email Address to not be the default
• Progress to the '4. Test' panel and save-and-continue-later
• Find the unsent mailing - the details listed above have been forgotten
• Mailing complains about no contacts on '1. Select Recipients' panel
• 'From Email Address' forgotten on '3. Mailing Content' panel