Gary,
No - that is not correct - the wantlist.xml carries the components you are using from the EXISTING dictionary of NIEM collection of "stuff".
See my reply on what goes into an IEPD. The idea is that an exchange designer should maximize reuse of items that are already in NIEM - and then only define domain specific new peices in your XSD that are not currently in NIEM - outside of the wantlist.xml items. This is exactly what we have in EDXL HAVE already - bits that are in the NIEM - and bits that OASIS has defined.
What I've done for CAM is take the NIEM Access database for v2.0 - convert it into an XML format for the dictionary and properties - and then written xslt - that will compare the CAM template of your exchange XSD (in this case EDXL) to that NIEM XML dictionary and build the wantlist.xml for you.
What NIEM teaches is doing this manually online using the SSGT to search and find the matching parts. Needless to say that is a tedious and slow process!
Fortunately the SSGT includes ability to save and then upload wantlist.xml - so I'm merely automating this all - so you can simply upload the wantlist.xml that CAM created instead - check that it works OK - and then you are done - minutes instead of days of work!
Hope that is clearer now.
Thanks, DW