1 Create one table:
CREATE TABLE notnull(
[not] character(1) COLLATE iso88591_bin
) COLLATE iso88591_bin ;
2 Click edit table, choose not null, it will display warning, click ok, then input a in default value.
3 click ok, it will pop error, please see the attachment.
In csql run the sql which has been generated in CM, it can run successfully.