Need help running AJAX from Web HTTP/HTML script

I am using 12.02 and attempting to run a AJAX operation from a Web HTTP/HTML script. I cannot use TruClient - IE or the AJAX script and click because the number of users to be run requires me to use threads. Not enough agent systems  to use processes.

A link on the page that starts this has the following structure:

<a name="j_id215:1:j_id263:0:j_id274:0:j_id303" 
      class="tse a4j-restore-focus-by-id" 
      id="j_id215:1:j_id263:0:j_id274:0:j_id303" 
      style="width: 100%; display: inline-block;" 
      onclick="A4J.AJAX.Submit('kr-timesheet-region','dashboard_form',event,
                        {'oncomplete':function(request,event,data)
                                 {showAccountSelector($(this));},'parameters':
 {'j_id215:1:j_id263:0:j_id274:0:j_id303':'j_id215:1:j_id263:0:j_id274:0:j_id303'}
                      ,'actionUrl':'/usda/Timesheet'} );return false;" 
     href="#">

2 web_custom_data calls are created when that link is clicked and the popup that appears has an account selected.

The first web_custom_data call does not give a failure and appears to do a POST with the following request body:

t=8090ms: 6418-byte request body for "https://wta.test.nfc.usda.gov/usda/Timesheet" (RelFrameId=1, Internal ID=34)
AJAXREQUEST=kr-timesheet-region&dashboard_form=dashboard_form

-  -  -  more stuff and at the end of the request - - - 

fPartialResponse=&j_id215%3A1%3Aj_id263%3A0%3Aj_id274%3A0%3Aj_id303=j_id215%3A1%3Aj_id263%3A0%3Aj_id274%3A0%3Aj_id303&

So, if I read this correctly, it is sending that I clicked that link.

I get back a bunch of stuff that seems to include the same code segment listed above. When executing the next recorded custom call, it fails with a mystery message from the app - no help from developers saying what that is other than null parameters. I have done multiple recordings and there is nothing to correlate.

I do not have access to the javascript as far as I know - still searching the massive download from the app.

So. The question is how do I run these and send back the correct strings to the app. I have tried using WireShark to get information but it is https and not much use there.