[horde] unknown date problem

[synrat]

imp. 4.04, horde 3.06, FreeBSD 5.4.

messages with GMT set to 0000 don't get their
dates displayed properly in the mailbox list.
I see "unknown date" in the date field instead.
When I click on the message, then the full date header
is displayed properly in the "Date" field, including 0000 GMT.
I suppose this could be blamed on the mail client ( in this
specific case Blackberry PDA's built in e-mail ), not supplying
the correct GMT offset, but this behavior can only be observed in IMP.
Mozilla, Outlook and Squirrel all detect the date properly for message 
listing.

The time zone is set to America/New York in horde.
Blackberries all have their timezones set to EST, but Research In Motion
tech. support is clueless why and where does the date header get set to
0000 GMT.

example.

Thu, 27 Oct 2005 18:41:22 +0000 GMT

Anyone ?

thanx a lot in advance.