Looking further, it only seems to apply to FAS200/3000 series, not even 2xxx/32xx, so this isn't valid I believe. I apologize.
How far away is the HTTP server? I'm wondering if the performance is better or worse.
If you need help getting it working better, it may be faster to open a support case if you're having issues and we can help troubleshoot it. I'd personally want to get a packet trace to see if you are getting fast network response times.