I wrote a windows service that checks a directory for some text files and then operates a number of different twain sources based on the text files – it has a mini protocol, sort of a file system messaging based approch for making twain devices available to the network.
How far have you come along on the project? If you have implemented the source that will take the commands I think I could help you with getting it to talk to another source, but I think you’ll need a helper app – like a windows service or something on the machine where the device is. Let me know if you’re interested.