Outlook 2003 - Cached Exchange Mode, the Gal, and check names

After a recent upgrade from Outlook 2000 to Outlook 2003 I've encountered
this problem several times.

My users are complaining that they can no longer put "firstname lastname" in
the
"To:" feild in a message, and use check names to complete the name from the
GAL.

With a little troubleshooting I have determined that if I have a user who
DOES NOT have cached exchange mode enabled, they can enter a name in the
"Firstname Lastname" format, click check names, and Outlook will complete the
name.

If a user DOES have cached exchange enabled, entering a name in the To:
feild as "Firstname Lastname" and hitting check names will result in the
check names dialog box opening indicating that "Outlook does not recognise
Firstname Lastname".

Is there a way to make the check names function successfully check names
entered in Firstname Lastname format when Cached exchange mode is enabled in
Outlook 2003?