Where does redirect from default search to apachesolr_search occur? We're using the apachesolr_search module on our site. (This is a site I inherited fully coded, so there's tons going on that I'm not intimately familiar with yet.) We have a search block that has been customized (see this post for details; we did eventually get the radio buttons to display, although in a really dirty, non-drupal way.)

I'm trying to get the form values on submit. Forgetting for a moment the radio buttons, I can't even figure out a way to get the value of the search box. Obviously it's getting passed to the solr search, but when I look at the Net panel in Firebug, there are no POST requests, only GET. In my submit function (which does run), I've tried print_r('$_POST'), echo $form_state['values']['search_box'] (where search_box is the element name of the actual form element), tried looping through $form_state and printing all key/value pairs... nothing. Not a single one of these returns anything. 

Obviously there's a redirect occurring somewhere that sends the value of the search_box to the solr search module to build the GET request, but I can't for the life of me figure out where it's happening. I think in order to see the values of the posted form, I'd need to intercept the values before the redirect - how do I do that?
Unless I'm mistaken, there is no redirect taking place. Instead the hook_search is used, which will pass the search params from the url.