Te envio el help del SET IDENTITY_INSERT que creo resolvera tu problema

Syntax

SET IDENTITY_INSERT [database.[owner.]]{table} {ON | OFF}

Arguments

database

Is the name of the database in which the specified table resides.

owner

Is the name of the table owner.

table

Is the name of a table with an identity column.

Remarks

At any time, only one table in a session can have the IDENTITY_INSERT property set to ON. If a table already has this property set to ON, and a SET IDENTITY_INSERT ON statement is issued for another table, Microsoft® SQL Server? returns an error message that states SET IDENTITY_INSERT is already ON and reports the table it is set ON for.
If the value inserted is larger than the current identity value for the table, SQL Server automatically uses the new inserted value as the current identity value.

The setting of SET IDENTITY_INSERT is set at execute or run time and not at parse time.

Permissions

SET IDENTITY_INSERT permissions default to all users.

Examples

This example creates a table with an identity column and shows how the SET IDENTITY_INSERT setting can be used to fill a gap in the identity values caused by a DELETE statement.

-- Create products table.

CREATE TABLE products (id int IDENTITY PRIMARY KEY, product varchar(40))

GO

-- Inserting values into products table.

INSERT INTO products (product) VALUES ('screwdriver')

INSERT INTO products (product) VALUES ('hammer')

INSERT INTO products (product) VALUES ('saw')

INSERT INTO products (product) VALUES ('shovel')

GO



-- Create a gap in the identity values.

DELETE products

WHERE product = 'saw'

GO



SELECT *

FROM products

GO



-- Attempt to insert an explicit ID value of 3;

-- should return a warning.

INSERT INTO products (id, product) VALUES(3, 'garden shovel')

GO

-- SET IDENTITY_INSERT to ON.

SET IDENTITY_INSERT products ON

GO



-- Attempt to insert an explicit ID value of 3

INSERT INTO products (id, product) VALUES(3, 'garden shovel').

GO



SELECT *

FROM products

GO

-- Drop products table.

DROP TABLE products

GO

-----Mensaje original-----
De:    Ariel Di Stefano [SMTP:ingsystems.com!ariel@mail.interserver.com.ar]
Enviado el:    viernes 30 de julio de 1999 11:26
Para:    Lista de Visual Basic
Asunto:    vb-esp : DUDA SQL SERVER

Co-listeros:

Tengo un problemita...

Trabajo con una tabla que tiene un campo ID, que es identity y en
determinado proceso,
debo actualizar los datos desde una tabla de COBOL....

Ahora bien cuando hago un delete de todos los registros de la tabla, y luego
vuelvo a insertarlos me genera el id a partir del ultimo antes de borrar los
registros...

Ej: ultimo ID: 154...
Borro todos los registros, y los inserto de nuevo desde cobol... y el primer
registro tiene ahora el ID 155.
El tema es que en tablas historicas yo guardo el ID viejo y cuando lo use no
lo va a encontrar..

RESUMEN: ¿Se puede borrar los registros y que el campo identity se resetee
(o vuelva a empezar de cero)?

Gracias desde ya.