Transform doesn't work on DeviceGroups field

Hi,

I receive events from my python script using zensendevent and try to use transform to add DeviceGroups field but it doesn't work.

My transform is simple:

if evt.eventClassMapping.find("StatystykiViaSyslog") != -1:

   evt.DeviceGroups = "BM"

If i set:

if evt.eventClassMapping.find("StatystykiViaSyslog") != -1:

   evt.summary = "BM"

it works fine.

Someone could tell me why I cannot set DeviceGroups field?

Regards,

Tommy