If you want to insert an id in the identity column, you need to use:

SET IDENTITY_INSERT table_name ON

https://msdn.microsoft.com/es-us/library/ms188059.aspx

Remember to set it OFF at the end of the script.

Possible Work-arounds

Well, since this answer doesn't seem to fullfill all requirements, I'm going to expand on it a bit more. The import/export wizard from the SQL Server Management Studio is basically an implementation of SQL Server Integration Services. If you need to build a package that has a few extra steps, you might want to consider SSIS as an option (it comes with SQL Server licenses so you don't have to pay any extras and it is available to use in Visual Studio). It will allow you to do the same task but also run SQL scripts on the database. It's a low code tool so it is very straight forward for this kind of situations.

Another option is to use the import wizard as it is to import into a "staging" table. So, instead of overwritting the destination table, you would:

1. Insert into a staging table (which should have the same structure as the destination table but making the IDENTITY column just an integer).
2. You import your data into this staging table.
3. Then you can run the following script to insert into the correct table.

SET IDENTITY_INSERT table_name ON

INSERT INTO table_name SELECT * FROM staging_table_name

SET IDENTITY_INSERT table_name OFF

Finally check that everything was inserted correctly and drop the staging table.

These are at least 2 possible ways to get the job done.