[VB.NET][XML] problem of namespace

[mucsy]

Hello !

I'm creating xml files (.3dxml) by using VB .NET.
I've got a problem with namespaces. I'd like to generate this line :

<Model_3dxml xmlns="..." xmlns:xsi="..." xsi:schemaLocation="http://www.monURL.com/">

I found two ways to do it.

First method :

Dim elemRoot As XmlElement
elemRoot = XmlDoc.CreateElement("Model_3dxml")
Dim elemRootAttr As XmlAttribute
elemRootAttr = XmlDoc.CreateAttribute("xsi", "schemaLocation", "http://www.monURL.com/")
elemRoot.Attributes.SetNamedItem(elemRootAttr)

I obtain :

<Model_3dxml xmlns="..." xmlns:xsi="..." d1p1:schemaLocation="" xmlns:d1p1="http://www.monURL.com"/>

Second Method :

Dim elemRoot As XmlElement
elemRoot = XmlDoc.CreateElement("Model_3dxml")
Dim elemRootAttr As XmlAttribute
elemRootAttr = xmlDoc.CreateAttribute("xsi:schemaLocation")
elemRootAttr.Value = "http://www.monURL.com"
elemRoot.Attributes.SetNamedItem(elemRootAttr)

I obtain :

<Model_3dxml xmlns="..." xmlns:xsi="..." schemaLocation="http://www.monURL.com"/>

these two XML files are wrong and I cannot use them...

What is the good way to do ?