I think that sys.syscolumns is a view that is related to ASE compatibility. You probably want to join SYSTAB, and SYSTABCOL.
select t.creator, t.table_name, t.table_id, c.column_type, c.nulls, c.width, c.default
from sys.systab t, sys.systabcol c
where t.table_id = c.table_id
You may have to also reference SYSIDX to get the primary key information.
References to the system tables and their structure can be found in the documentation. In most cases you can use the SQLAnywhere v10 documentation to find answers about Sybase ASA.