Luca, thanks for all of your help.
I contacted one of our Linux guys here and he helped me to solve the issue.
After some troubleshooting, he told me to use both the -H and -I options.
The -H to define the actual host name of the server I am monitoring, and the -I option to define the SOAP monitoring server. See below.
*./check_http -s -H mecprvagswebw01 ****-I 10.35.1.2 -u 'http://10.35.1.2/liteclient2/Funclist.aspx?cap=Map&service=Demographics/ESRI_00-08PopGrwth_US_2D&instance=&type=MapServer&server=http://10.211.1.2' -w 15 -c 20 --string=PASS
HTTP OK: HTTP/1.1 200 OK - 2554 bytes in 2.006 second response time |time=2.005849s;15.000000;20.000000;0.000000 size=2554B;;;0*
To answer your last question. Our setup here is a unique one. We use that custom application server (SOAP) to check the application on our systems instead of going directly to the server. From the web page (10.35.1.2/liteclient2) there is a list of all of our servers, each with 70+ content check links. We just click the specific link for the server we want to check, in this case (ESRI_00-08PopGrwth_US_2D), it goes out to that server and returns a Pass or Fail.
I wanted to figure this out so that on the Nagios GUI, I can have all of the content checks listed under each server.
I appreciate your help. You really helped me to get my creative juices flowing, which helped the Linux guy figure it out.