Serialize K2ROM Object

Has anyone been able to serialize a K2ROM object to xml, specifically the WorkListItem object?

I've tried with:

Dim aWorkListItem As K2ROM.WorklistItem
Dim aProcessInstance As K2ROM.ProcessInstance

strSerialNo = "XYZ"

aWorkListItem = aServerConnection.OpenWorklistItem(strSerialNo, "ASP", True, False)

Dim fs As New System.IO.FileStream("c: empk2workitem.xml", System.IO.FileMode.Create)
Dim writer As New XmlTextWriter(fs, Encoding.Unicode)

Dim x As System.Xml.Serialization.XmlSerializer = New System.Xml.Serialization.XmlSerializer(GetType(K2ROM.ProcessInstance))
x.Serialize(writer, aWorkListItem.ProcessInstance)
writer.Close()

But it doesn't work. It only gives me top level xml, no fields. It must be marked serializable then???

I'm trying to find a quick efficient way to get all data fields and xmlfields to xml file.

Thanks