Extension Hooking

Ok, I know this is probably fairly simple, but I am having a touch of trouble. I am trying to create an extension that hooks into an existing extension freeform. I was thinking I would use the freeform_module_insert_end hook. ( see : http://www.solspace.com/software/detail/freeform/ ) What I want to do is catch the form submission of a freeform entry IF the name has been entered in the settings. (see attached image “extension_1.jpg”)

So…

If the user entered “test” in the settings, When the form was submit, the extension would scan the URL for a segment that matches the settings options. (In this case - “test”) If there was a match, the extension writes a cookie named “<some prefix>_test” with the value of “test” that expires in 360 days.

I hope this makes sense. I have tried writing it several different ways, but I am fairly new to EE and php.

I have a lang file and get the ext to run, install, show settings, and get populated in the DB, just not WORK!… lol

Thanks in advance,

Brian