Insert SQL 2008 Parent And Child Rows In A Single Transaction?

First, a little background (greatly simplified): I have two classes, one called Entity and one called Item which a subclass of Entity. They each store their individual properties in seperate SQL 2008 tables using TableAdapters generated by a strongly typed DataSet. The Entity class has a Save() method that looks like this:

Public Sub Save()
entityTableAdapter.Update(entityRow)
End Sub

[Code]....

Indeed, the SQL table does not contain a row in the Entity table with the necessary ID at this point because the transaction is not complete.

My goal is to prevent the Entity record from being inserted if inserting the Item record fails. I could write code to delete the Entity record again, but this does not seem very elegant to me...