Nginx config seeing asset_controller, but not loading file.

[eluser]talkingnews[/eluser]
PyroCMS is a CMS built on top of Codeigniter, and I'm using a module called Pyrostreams.
But the reason I'm posting here is because this is actually about nginx config for CI, as Apache works fine and it's a CI method being called that isn't working here.

Everything about the entire setup works fine on nginx, except it appears to be trying to call a couple of files from a "virtual" directory, which doesn't exist.

Here's the log entry:

"GET /streams_core/field_asset/css/datetime/datepicker.css HTTP/1.1" 404

The file actually exists in

/www/cms/system/cms/modules/streams_core/field_types/datetime/css

The author says it works just fine in Apache, and isn't able to install nginx himself.

However, here's what he replied with:

Looks like it is trying to access the URL as an actual file. The files technically doesn't exist in that location, so it may have a problem with that.

The assets are actually loaded via PHP - there is a field_asset controller under the streams_core module that takes the file name in the URL and outputs it.

It's strange that there would be a compete 404 since it should map anything in index.php/streams_core/field_asset to a function. If you go to index.php/streams_core/field_asset, do you get a blank page?

And yes, I do get a blank page, rather than a 404, so I suppose that shows it's hitting the controller OK?

Here's the nginx config that Pyrocms suggest:
http://docs.pyrocms.com/2.1/manual/index...th-php-fpm

Here's the complete nginx config file I'm using:
https://gist.github.com/3419706

And here's the .htaccess file that comes with the application (for those using Apache)
https://gist.github.com/3419710

Been round in a few circles trying to figure this out - a bit lost now. Any ideas would be appreciated! Thanks.