design for a silkroad bot well there is nothing special about or secret.
The idea of a bot is to send packets to server and mabye even block packets from the server. so all you need is a proxy which accept a connection from the client and connects to the real server. then you can send anything you want to the server and also read the packets and ect.
An good example of this proxy will be the SilkroadSecurityApi it is in C# but it's .net and I don't know if you're using vb.net but if you do you could use it to create your proxy with it. btw you can also convert the example proxy code to vb.net with some free online tools so you can read it.