RESTful API - WooCommerce REST API requests with swirl error

I recently upgraded to the latest version of WooCommerce 2.1, which includes the new RESTful API . I don't have much experience with cURL or RESTful APIs, but I thought I was playing.

My site is sergedenimes.com, and I have SSL installed on the server.

If I run curl https://sergedenimes.com/wc-api/v1, I get a nice long json output bit as follows:

{
   "store":{
      "name":"Serge DeNimes",
      "description":"Original, Urban T-Shirts Of The Highest Quality by Oliver Proudlock",
      "URL":"http:\/\/sergedenimes.com",
      "wc_version":"2.1.2",
      "routes":{
         "\/":{
            "supports":[
               "HEAD",
               "GET"
            ],
            "meta":{
               "self":"http:\/\/sergedenimes.com\/wc-api\/v1\/"
            }
         },
         "\/customers":{ etc.....

This suggests that api itself is working. However, when I pass a request that uses authentication:

curl https://sergedenimes.com/wc-api/v1/orders -u my_key:my_secret

I get this in response:

{
   "errors":[
      {
         "code":"woocommerce_api_authentication_error",
         "message":"Consumer Key is missing"
      }
   ]
}

Is my syntax correct? I set my key and secret under the WP administrator and passed the values, but it seems that I am not passing it with my request.

Any ideas?