Need help in web service connection.

Dear all,

I want to get data from external content type thru web service and those data want to display in share point 2010 external list: To do this I have followed the below steps:

Step: I have opened that website from share point 2010 designer and created external content type. While creating external content type in the dropdown list as we can see the below option

.NET Type

WCF Web Service

SQL Server

I don't know how to use .NET Type from share point 2010 designer option so I chosen the WCF Web Service option. I have created web service using Visual Studio 2008 to get the customer information. While placing the normal web service URL in WCF web service. Its displaying error like can not create xml document.

Below is my query:

1)      What is the mistake I am making or how can I use normal .net web service as WCF web service in share point 2010 designer.

2)      Or any other alternate way to get the external data in share point list I mean can we call the web service  from share point list itself instead of going for designer.

3)      How can I use .NET Type (as I mentioned above) as data source from SP2010 designer with a simple example in this case.

Your help is always heartily appreciated. Thanks in advance.