[Inf-IT DAVcl] Only one address book visible

Hi everybody, I just set up DAViCal + infcloud and most things are working fine so far. But I can't get infcloud to display more than the default address book. The preview at https://www.inf-it.com/infcloud/ looked like multiple address books and even groups are supported, but I can't get none of them working. Is there anything I could be missing? regards, Silvio