Web Services in PDA device with WinCE .NET 4.10

Hi,
I am working in a scanner PDA with WinCE .NET 4.10.
I use Visual Studio 2003 to build a SmartDevice VB progam.
In the project, I add a web reference to connect to an exist web services.
The VS will generate a Reference.vb from the WSDL I select.

VB Code:

Public Function DOinput(<System.Xml.Serialization.XmlElementAttribute([COLOR=Red]Form[/COLOR]:=System.Xml.Schema.XmlSchemaForm.Unqualified)> ByVal input As String) As <System.Xml.Serialization.XmlElementAttribute("DOinputReturn", [COLOR=Red]Form[/COLOR]:=System.Xml.Schema.XmlSchemaForm.Unqualified)> String
            Dim results() As Object = Me.Invoke("DOinput", New Object() {input})
            Return CType(results(0),String)
End Function

It shows "cannot find the field or attribute 'Form" while building project.
But it's OK when I create a standard application project with the same wen reference added.

Please help.

thanks and best Regards,
Andy