Mocking a datacontext database

Totally new to typemock and with only a few months c# experience so I'm not even sure if what I'm trying to do can be done. Some advice would definitely be appreciated :)

I would like to be able to populate a datacontext database with data from an xml file for testing purposes. The code I have unsuccessfully tried is below which may help understand my approach:

Mock sdc = MockManager.Mock(typeof(ServerDataContext));
ServerDataContext dc1 = new ServerDataContext();

XDocument xd = XDocument.Load(@"c:xmlfile.xml");

var cs = from post in xd.Descendants("customers")
select new customer
{
id = Int32.Parse(post.Element("id").Value)
oh_id = Int32.Parse(post.Element("oh_id").Value)
};

var oh = from post in xd.Descendants("order_headers")
select new order_header
{
id = Int32.Parse(post.Element("id").Value)
ol_id = Int32.Parse(post.Element("ol_id).Value)
};

var ol = from post in xd.Descendants("orderlines")
select new orderline
{
id = Int32.Parse(post.Element("id").Value)
};

dc1.customers.InsertAllOnSubmit(cs);
dc1.orderlines.InsertAllOnSubmit(ol);
dc1.order_headers.InsertAllOnSubmit(oh);

This obviously fails because the mocked datacontext has not been initialized with empty tables but with null values. Is there someway of mocking the datacontext and initializing the tables? Or is there someway of mocking a table? I don't really want to have to rely on a connection to an empty database.

I have read articles about using lists to fake return values from specific queries but the problem I have with this is that I return a customer which has joins to order headers which has joins to order lines which can't be represented in a list.

Any suggestions greatfully appreciated!