first, radio buttons and combo boxes do not force the input to be anything. if you connect to the http port with telnet you can type whatever you want as a value for that field.
i do not know what is available in asp. in asp.net (more specifically ado.net) this example might help:
http://www.csharp-station.com/Tutori.../Lesson06.aspx
i just realized that this is c#, but you can probably find one that is in vb