Doesn't seem to be working, can't figure out how to debug

Hi, sorry to bug you with a support request, I just need some help getting pointed in the right direction.

The client's Drupal site uses the Flickr module to display a feed of flickr images on the homepage. The Flickr API is dropping support for HTTP and switching exclusively to HTTPS soon - at the end of this month I think. But our web host says that HTTPS requests from the web server need to go through a proxy for some reason.

This module seems to be a better and more scalable answer than hacking all the requests in the Flickr module, and it does appear to be using the drupal_http_request() function, so I'm hoping that this module will work to funnel the flickr API requests through the proxy.

I've installed the module, enabled it, and set the configuration for both "Override Drupal HTTP Request" and "Enable Debug Output", but the flickr stream does not show up on the homepage. Devel is enabled.

I'm not seeing any debugging information either. I've checked the Watchdog log, the Apache error log and Apache access log to look for any information that might help me to debug the request/s but I'm not seeing anything.

Strangely even though I have configured the proxy to be HTTPS only and instructed it to ignore requests to localhost and the live site (for stage_file_proxy requests for missing images on the Test site), I did see an error in the Watchdog log for some missing imagecache images, which when viewed directly on the Test site does appear to list some debugging output in devel, despite the request being HTTP and from the live site, which is excluded.

Here is my config in the Test site's settings.php (with actual values modified to protect the innocent):

$conf['https_proxy'] = array(
  'server' => 'proxy.host.com',
  'port' => '1234',
  'exceptions' => array('localhost', 'www.live.site.com'),
);

I've contacted the web host to see if there is any information I'm missing about the proxy, but any advice you can give to how to go about debugging the proxy calls would be much appreciated.

Thanks,

Scott