I've discussed this behaviour with the Development.
Database Studio seams really to restrict functions of users belinging to one usergroup.
Via SQLCLI (and of course SQL Studio) you should still be able to see and create tables as a member of a usergroup with resource priviledge
http://maxdb.sap.com/doc/7_8/45/7d7a31f3dd1956e10000000a11466f/frameset.htm
... and I suppose you are able to run queries on the tables of schema BWALLE logged on as BWPROGI in SQL editor of Database Studio. At least I could in my DB.
This will be corrected.
Until than you should use SQL Studio and SQLCLI.
Regards Balázs