Null Values When Quering Sql Server From VC++

Hello, i´m inserting values in a table defined as above,

/********
create table SERVICE_TYPE (
PK_TYPE numeric(8) not null IDENTITY,
TYPE nvarchar(32) not null unique,
DESCRIPTION nvarchar(256) null default(''),
USER_VISIBLE numeric(1)not null,
constraint PK_SERVICE_TYPE primary key (PK_TYPE)
)
go
**********/

these values are inserted throug ODBC with VC++,
in the case of the DESCRIPTION Column, i´m sending null strings CString(""). this value will be filled after.
What happens is that, when i query the database to show the records in this table, the database shows, for example:

PK_TYPE TYPE DESCRIPTION USER_VISIBLE
--------- ------ ------------------- -------------
1 1 (null) 1

i dont want to show the "(null)" value in the column DESCRIPTION, but a null string like ""

can anyone help me , thanks

Cristovão