"Ruslany Add Slash Rule" doesn't work in my environment

I can't get the 'Ruslany add slash' rule to work in my environment.

- all traffic comes into an ARR server in the DMZ

- URL rewrite (not redirect) rules on the ARR server rewritehttp://deptname.mysite.com to http://internal.mysite.com/deptname .

- a "Ruslany Add Slash Rule" is on the ARR server, at the top of the rules list.

- the'internal.mysite.com' site is in a protected DMZ area (a different server than the ARR server), and contains the actual content

But with the "Ruslany Add Slash Rule" to add a slash,http://deptname.mysite.com does not get rewritten tohttp://internal.mysite.com/deptname/ .  Andhttp://deptname.mysite.com/sectioname (without trailing slash) doesn't get rewritten tohttp://internal.mysite.com/deptname/sectionname/ (with trailing slash).

This URL does work http://deptname.mysite.com/sectionname/ (with trailing slash) does get rewritten tohttp://internal.mysite.com/deptname/sectionname/ .

I have tried numerous variations on the 'add slash' rule:

• <div style="background: #dddddd;"> I have put the 'add slash' rule at the top of the URL rewrite rules on the internal.mysite.com IIS site.</div>
• <div style="background: #dddddd;">I have tried setting the "Ruslany Add Slash Rule" to enable or disable 'stop processing'.</div>
• <div style="background: #dddddd;">I have put the rule at the server level and site levels on the ARR server and the internal.mysite.com IIS site level (with only one enabled at the same time)</div>

Nothing works. A URL without the trailing slash results in a 404. And haven't been able to set up a Failed Request Tracing Rule that will catch the problem (without getting tons of FRT, since this is a live site).

This is on Server 2008, IIS 7.5, fully patched.

How can I make this work?

Thanks...Rick...