ADO.NET's WriteXML have difference behaviour between .NET 1.1 and .NET 2.0

I have a dataset which contains two tables, one is master and another is
child table with a relation join between tables.

When I use DataSet.WriteXML in .NET 2.0, it shows as:

<aDataSet>
<MasterTable ID="1" ............... />
<ChildTable ID="1" .................. />
...
</aDataSet>

It is not my expected (which used in DataSet.WriteXML on .NET 1.1) as:

<aDataSet>
<MasterTable ID="1" ............... >
<ChildTable ID="1" .................. />
...
</MasterTable>
</aDataSet>



ADO.NET's WriteXML have difference behaviour between .NET 1.1 and .NET 2.0?
How to fix it?