This: http://communities.vmware.com/message/2066600#2066600
led me to this: http://communities.vmware.com/docs/DOC-19177
which has a linked PDF: http://communities.vmware.com/servlet/JiveServlet/download/19177-1-87310/How%20to%20ThinApp%20Windows%20Server%202003%20Service%20Pack%202%20Administration%20Tools%20Pack.pdf
which solved this problem for me.
Yay for search engines (which I haven been using all day, but in the end did turn up what I need.