I answer to myself. 🙂
It is sufficient:
1. Add a new partition by using the “setup” menu
2. Create a new profile (= database) in the new partition
2. Deactivate default profile in /dev/hda3
Two more things, anyway:
a) by using web-administration you cannot choose the type of new partition: I mean I cannot choose between primary or extended. The program creates an extended one, in any case.
Maybe – I’m asking for a confirmation here – you can get a new partition of primary type by using the fdisk command in console.
b) The hda3 partition stays there, of course, empty. This is not fine to see but I think there is no way to avoid it.
Maybe you can use some third part programs (like Partition Magic or whatsoever) in order to “enlarge” partition hda3 instead of creating a new hda4. This way you have a better geometry of your disk
The most imporatnt thing, however is that I did not find any limit to enlarge the space for Database/Profile beside to that allocated directly by the ZS CF image.