Our computers have Internet Explorer 11 and Acrobat XI installed. We
have a single web application that requires IE 9. So I virtualized IE 9
using a template, no problem there. While running the web application in
virtual IE 9 it needs to open pdf files externally in Acrobat (not using
the plugin inside of IE). The documentation states the following to in
order to run a native application in a virtual environment:

To enable a natively installed application to launch in a virtual
environment: click on the Multiple button next to the Startup File
field, in the File column, enter the local path of the natively
installed application.

So I added @PROGRAMFILESX86@\Adobe\Acrobat 11.0\Acrobat.exe

But when I run my virtual IE 9 app and click on a link to a pdf the
download manager briefly flashes but the pdf doesn't open in Acrobat, it
just disappears into never, never land. If I check Acrobat to Auto Start
with the virtual app, it does, so I know that is working.

What else do I need to do so that my virtual IE9 app will open pdf files
in Acrobat?