Get Name of Attribute of Web Online

I created a webservice and database in SQL Server 2008.. and a device connect to webservice by Ksoap2 to access database..That is webservice that
To get a value of attribute of database,I will get based in name of attribute
In this case,I can do because I known name of attribute
If I have a webservice that I get online...What must i do to know name of attribute in web application...Thank all