Wrong time zone if I send appointment to Blackberry Z10

Since I am using Blackberry Z10 every appointment sent from GroupWise 8 oder now GroupWise 2012 has wrong or no time zone!
I must adjust every appointment manually at my BB device. I am not using BES! Appointments are only sent by mail to BB10.
If I get appointments from Outlook users, all is O.K.

I hoped it had been corrected in new release of GroupWise 2012, but error is the same since GW8.

Hope to get help, because I hav to migrate some clients next week too, with BB devices like mine.

Karl-Heinz Rausch
DatenRausch GmbH
Germany