Well, I was able to send out a link that opens up the form but not able to open it up in a modify window.
Here is my link: http://webservername:8080/arsys/servlet/...D0000000000100"
Even though I query for specific case, it just opens up the Help Desk form in create a new window.

ARS 6 with Mid Tier 5.1.2

Here is the missing part:

servlet/ViewFormServlet?formalias=HPDHelpdesk&server=arservername&qual=%27Case%20ID%27%3D"HD0000000000542"