Hi SoCalMacDude,
You should be able to accomplish this without a web viewer with TCPDirect plugin (www.fusionplugins.com/tcpdirect). It will allow you to send http request headers built up from filemaker data to a web server, and receive the response into filemaker where you will then be able to parse out the data you want using the various text functions.
In order to do this you will also require another application which will allow you to view outgoing / incoming tcp packets on your network interface. If you are using a mac then check out the command line tool tcpflow (http://www.circlemud.org/~jelson/software/tcpflow/) which will display header information and received header/data on an interface you specify.
So in other words what you would do is run tcpflow or an equivalent program, go into your web browser as usual and go to the URL, enter your code, hit submit etc, but check out everything thats happening underneath the hood, what the headers being sent/received are, and contain etc.
Then using TCPdirect, rebuild the same thing by sending the same header, but only this time the information you receive will come into FileMaker, from there you can send more tcp requests, or parse out the data you require.
The end result is quite elegant for a Filemaker database, no need for a web viewer, just a simple filemaker field where you enter your code, and a filemaker button attached to a script which handles the plugin function calls, and the data parsing.