To use the msgxml tool to perform the HL7 to XML translation and the XML back to HL7 translation:
D:\test>msgxml --toxml exercise4.vmd before.txt xml.txt
where exercise4.vmd is the name of your VMD file and before.txt is your HL7 message. The xml.txt file is where your converted XML output is saved.
If you would like more information regarding the msgxml utility, see msgxml.