webservices 生产xml format问题

[klan]

我有如下定义的class，
[XmlRoot("iSAMS")]
public class iSAMS
{
public order[] ORDERS { get; set; }
}

public class order
{
public order()
{
//set default
Company = "";
}

[XmlAttribute]
public string Company { get; set; }

public item[] items { get; set; }
}

public class item
{
public item()
{
Availability = ""; }

[XmlAttribute]
public string Availability { get; set; } }


webservice如何生成这样的xml返回

<soap:Envelope>
<soap:Body>
<GetOrdersResponse>
<GetOrdersResult>
<iSAMS>
<ORDERS changeset="-1"> <------- 这里有添加新的属性-->
<order Company="aaa">
<item Availability="CN"/> <--- item不是在items下，而是在order下---->
<item Availability="US"/>
</order>
</ORDERS>
</iSAMS>
</GetOrdersResult>
</GetOrdersResponse>
</soap:Body>
</soap:Envelope>

需要在class以及它的属性里面添加什么样的attribute呢？谢谢

webservice 看上去这样

[WebMethod]
public iSAMS GetOrders()
{
return new iSAMS
{
ORDERS = new[]{
new order{items= new[] {new item{},new item{}}}, new order{}
}
};
}