Inserting a default Value

I have populated an SQLdata table from an XML datasource usinmg the bulk command. In my SQL table is a new column that is not in the XML table which I would like to set to a default value.

Would anyone know the best way to do this. So far I can's see how to add this value in the Bulk command. I am happy to create a new command that updates all the null values of this field to a default value but can't seem to do this either as a SQLdatasource or a APP Code/ Dataset.

Any suggestions or examples where I can do this.

Many thanks in advance

A DataColumn has a DefaultValue property - seeMSDN for usage:

private void MakeTable()
{
// Create a DataTable.
DataTable table = new DataTable("Product");

// Create a DataColumn and set various properties.
DataColumn column = new DataColumn();
column.DataType = System.Type.GetType("System.Decimal");
column.AllowDBNull = false;
column.Caption = "Price";
column.ColumnName = "Price";
column.DefaultValue = 25;

// Add the column to the table.
table.Columns.Add(column);

// Add 10 rows and set values.
DataRow row;
for(int i = 0; i < 10; i++)
{
row = table.NewRow();
row["Price"] = i + 1;

// Be sure to add the new row to the
// DataRowCollection.
table.Rows.Add(row);
}
}

insert/update trigger

Tbl1 inserts 1 record(with some fields populated) in tbl2. then I need get values from tbl3 to populate the rest of the fields in tbl2(update the record).
tbl1 = tblallBag_data
tbl2 = tblBag_data
tbl3 = tblShipping_sched

I created a trigger in tbl1 to insert a record into tbl2 and it works fine.

CREATE TRIGGER trgtblBag_Data ON dbo.tbltblallBag_data
FOR INSERT
AS

INSERT INTO tblBag_data (work_ord_num, work_ord_line_num, bag_num, bag_scanned_by, bag_date_scanned, bag_quantity)
SELECT work_ord_num, work_ord_line_num, bag_num, bag_scanned_by, bag_date_scanned, bag_quantity
FROM inserted

How can I update tbl2?
Should I create another trigger to update tbl2?
Should I join the two tbls(tbl2 & tbl3) to find
@.work_ord_num = work_ord_num , @.work_ord_line_num = work_ord_line_num

Thanks for your help!tbl2 and tbl3 should be joined with inserted.