Is CacheExclude working to serve dynamic php content to anonymous users?

I'm trying to get the Drupal5 version of this module to work in order to display dynamic content to anonymous users that comes from a node with content type php. This doesn't work.
Stepping through the code with a debugger, I can see that function cacheexclude_init() correctly identifies my path to be excluded and sets $GLOBALS['conf']['cache'] = FALSE;

However, the page is still added to the cache, so the next time cacheexclude_init is called, it is already to late, as this is being called from these lines in _drupal_cache_init in bootstrap.inc:

  elseif ($phase == DRUPAL_BOOTSTRAP_LATE_PAGE_CACHE) {
    if ($cache = page_get_cache()) {
      if (variable_get('cache', CACHE_DISABLED) == CACHE_AGGRESSIVE) {
        drupal_page_cache_header($cache);
        exit();
      }
      elseif (variable_get('cache', CACHE_DISABLED) == CACHE_NORMAL) {
        require_once './includes/module.inc';
        bootstrap_invoke_all('init');
        drupal_page_cache_header($cache);
        bootstrap_invoke_all('exit');
        exit();
      }
    }
    require_once './includes/module.inc';
  }

bootstrap_invoke_all('init'); will call the function cacheexclude_init, but at this point the cached page is already being served.
So as far as I understand this, $cache = page_get_cache() would need to fail in order for this to work. I'm just starting to look at this code and I guess the page should never have been added to the cache in the first place due to the cacheexclude module.
I have cleared the cache and modified the node in question. Caching is set to normal.

What am I doing wrong here? Is the CacheExclude module is known to be working for my use case?
Any help would be appreciated.