timestamp data type and null value

Hello there:

I am trying to move one of our databases from MS SQL
to PostgreSQL and having trouble. One of our table
columns is a timestamp type and the contents in MS SQL
is nulls. When defined for PostgreSQL, I specifically did
not include the "NOT NULL" attribute to this column, but
when we issue an INSERT with the null, it fails with an
error indicating that nulls are not allowed. What can I do
to either get the timestamp data type to permit null values
or to redefine my column to accept a timestamp-like type
and nulls.

Thanks,
--
William L. James
I/NET, Inc.
Email: mailto:bjames(at)inetmi(dot)com
WWW: http://www.inetmi.com