problem recreating folder previously deleted from GW client

Hi,
we are synchronizing items into GW folder. If the folder doesn't exist,
we create the folder. The problem is if the user deletes the folder from
GroupWise Client (Windows), then the createItem request fails with error:

The name of the folder is not unique. (rcode: 60164)

The folder is not visible in getFolderList response

view[0] = "id";
view[1] = "name";

gwFolders = es.getFolderList("folders",view,true,false,false);

The folder is not visible in the GroupWise Client and it can be created
from Windows GroupWise Client without a problem, but SOAP returns 'the
name of the folder is not unique'.

The only thing that allows us to create the folder again using SOAP is
to restart the POA :-(

Is the POA somehow caching the folder structure for SOAP ?
What can I do to create the folder without restarting POA ?

Thanks,
Petr