[SQLObject] addColumn question

[artman <cle...@mo...>]

Hi,
I'm using PostgreSql 8.1, and I have two classes below:

class Department(SqlObject):
    attr1 = StringCol(...)
    ...
    chief = ForeignKey('Employee')

class Employee(SqlObject):
    attr2 = StringCol(...)
    ...
    department = ForeignKey('Department')

I know because they are referred by each other, I can't create them in any 
order.
So I modify the Department class like this:

class Department(SqlObject):
    attr1 = StringCol(...)
    ...
Now I think I can create the two classes and add new column to the 
Department class:
Department.createTable()
Employee.createTable()
Department.sqlmeta.addColumn(ForeignKey('Employee',notNone=True),changeSchema=True)
But there is an error in the sql command:
ALTER TABLE department ADD COLUMN employee_id INT NOT NULL, CONSTRAINT 
employee_id_exists FOREIGN KEY (employee_id) REFERENCES employee (id)
Is it a bug or I'm using addColumn in a wrong way? and HOW CAN I GIVE A NAME 
TO THE ADDED FOREIGNKEY?
Thanks in advance!