populate dataset fk value using xmlschema xsd

[chudq]

I am trying to use xml shema to load xml file to a dataset. Here are
two tables:

Table Item:
Item_ID (key)
Name
Category_ID (foreign key from table Category)

Table Category:
Category_ID (key)
Description

I set relationship between 2 tables as commented above

Here is a part of my xml file:

<Category DisplayName="Cat 1">
<Item Name="Item 1" />
<Item Name="Item 2" />
<Item Name="Item 3" />
</Category>
<Category DisplayName="Cat 2">
<Item Name="Item 4" />
<Item Name="Item 5" />
<Item Name="Item 6" />
</Category>

Here are some codes:

// MySchema (or MySchema.xsd) is a schema defining two tabels in
above
// using VS dataset designer in the porject
private MySchema m_Shema = new MySchema;

string sFile = @"C:\temp\myItems.xml";
this.m_Shema.ReadXml(sFile);

The problem is that table Item does not have any values for
Category_ID column. They are empty! Based on the relationship, it
should be key values in Category table (Category table is fine). How
can I set the schema so that ReadXML() will read the relationship
values correctly in tabe Item?

[chudq]

After calling ReadXML(), the Table Category is:

Category_ID Description
0 Cat 1
1 Cat 2

and the table Item:

Item_ID Name Category_ID
0 Item 1
1 Item 2
2 Item 3
3 Item 4
4 Item 5
5 Item 6

What I expected for table Item should be:

Item_ID Name Category_ID
0 Item 1 Cat 1
1 Item 2 Cat 1
2 Item 3 Cat 1
3 Item 4 Cat 2
4 Item 5 Cat 2
5 Item 6 Cat 2

The relationship is defined between Item and Category tables, but the
result of Category_ID in table Item is empty.