I do not have any documents handy that can answer your query in detial. However in a nutshell this happens:
Connectware (or any other similar middle-ware) communicate to Baan via DDC (Distributed Data Collection) Drivers.
The user scans the data (order no., position etc) into Connectware UI. Connectware validates and sends the data in a message to the DDC driver. The message contains all the needed information like the Function Server (FS) name, function name and the argument list (user scanned data) etc.
The DDC Driver sends the message (request) to Baan's DDC Server, which interpets it and invokes FS's function by passing the arguments list. The Function Server gets executed (similar to that of a Baan Session execution) and sends the success / failure status to the DDC Server. The Server sends back the function's response (reply) to the UI through the DDC Driver.