Create XML Fields and then Update Value from VS2005

Hi plz help me , how to update XML fields data (Process level or activity level) when i have a XML field named "Names" with two columns FirstName and Other, m trying this but i know this is not right as i want to insert data in those colums i have created within the "Names" field.

like this in K2.net this is it's schema:

<xs:schema id="DataGrid" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata" attributeFormDefault="qualified" elementFormDefault="qualified">
<xs:element name="K2DataGridRoot">
<xs:complexType>
<xs:sequence>
<xs:element name="Item">
<xs:complexType>
<xs:sequence>
<xs:element name="FirstName" type="xs:String" minOccurs="0"/>
<xs:element name="Other" type="xs:String" minOccurs="0"/>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:schema>"

m using something like this plz give me some example but i want to assign values to FirstName and other field but don't know how 2 do:

oWorkListItem.ActivityInstanceDestination.XmlFields["Names"].Value = User.Identity.Name;

Thank's Pankaj