Set xmlrpc.net service url at runtime

I like to interact with some of my wordpress blogs through xmlrpc interface. During my research I found xml-rpc.net-Library (www.xml-rpc.net) which works really fine except for one thing.

I build my xmlrpc.net instance like this:

[XmlRpcUrlAttribute("http://my-example-blog.com/xmlrpc.php")]
public class WP : XmlRpcClientProtocol
{
    public WP()
    {

    }

    ...
}

But I want to set the xmlrpc-Url dynamically during runtime. So I like to add more blogs during the UI at runtime and don’t want to implement each blog “hard-coded”.

Does anybody had a same problem and can help me? Is there another possibility within xmlrpc.net-library or do you know another good xmlrpc library?

Greets,
Raffi