I need to be able to manipulate a XML with a schema like this:

```
<?xml version='1.0' encoding='UTF-8' standalone='no'?>
<SOAP-ENVELOPE:Envelope xmlns:SOAP-ENVELOPE='http://schemas.xmlsoap.org/soap/envelope/'>
<SOAP-ENVELOPE:Header>
    <Authorization>
        <FromURI/>
        <User/>
        <Password/>
        <TimeStamp/>
    </Authorization>
    <Notification>
        <NotificationURL/>
        <NotificationExpiration/>
        <NotificationID/>
        <MustNotify/>
    </Notification>
</SOAP-ENVELOPE:Header>
<SOAP-ENVELOPE:Body SOAP-ENVELOPE:encodingStyle='http://schemas.xmlsoap.org/soap/encoding/'>
</SOAP-ENVELOPE:Body>

```

I need to add the data for FromURI, User, Password, NotificiationURL, MustNotify, etc and within the body I sill need to add dynamically:

```
<SOAPSDK4:APIOperation xmlns:SOAPSDK4="http://www.someserver.com/message/">
</SOAPSDK4:APIOperation>

```

To finally construct the structure within APIOperation that is needed for the web service but can be easily done using XDocument to create a tree.

I've been having troubles to find information for a week on how to manipulate data within the envelope and here I need to do so with tree different levels.