In the ChatProvider implementation code ,
You can override the method and use another way to return the connection string :
for example:
public class ExampleProvider : ChatProvider
{
public override string GetConnectionString()
{
//return base.GetConnectionString();//the default implementation is "ConnectionString"
//now use another way to return the string :
return System.Configuration.ConfigurationSettings.AppSettings["AnotherConnectionString"];
}
....
}