Small note on Indigo and ASMX interoperability
If you want to consume an Indigo Web service from the 'Add Web Reference ..' dialog within Visual Studio .NET or with the command line tool wsdl.exe, or with WsContractFirst, the Indigo service must be using Datagrams over HTTP.
Dialogs and/or TCP are not supported by the .NET Framework 1.x (which is the common base for all three tools).