Manuel
It might depend on what your overall goal is. We have incorporated HL7 functionality into our VFP application. We use a tool from ORION called Symphonia to create a listener. They have some great VB examples that come with it, but they haven't been able to get all the functionality working with me and VFP. But the good news is that I can receive the messages, then I have code to parse the message and pull out the data I want. The Symphonia control will actually send ack's back to the sender and you can send hl7 messages of your own. The symphonia tool walks you though building a set of messages that you want to send or receive and then it generates an ActiveX/DLL. From this you create and parse your messages.
I will email you the Parser Program if you want.
Kirk