Proxies blocking comments function on blogs?

Hi

I'm trying to do some manual high pr blog post commenting but I think my IP address has been blocked (the comment is accepted but doesn't go live, this is on automatic comment approve blogs).

Ive tried using a proxy "hidemyass" but when I go to the same blogs it seems like comments have been turned off. I think this is because the site knows Im using a proxy?

Can anyone tell me if this sounds right and if so if there a way to get around it so I can use a proxy without the comments function being disabled?

Thanks

use the same proxies you have from HMA and try placing a comment without placing a link and see how it goes, if the comment is approved and live then there are links filter on that blog, if not try using private proxies ...