Issues with request_params

I am trying to use the request_params feature of formula so I can send a parameter using query string. Here is what I have defined.

However, when when I use the URL with those parameters in the query string, they are not being recognized for some reason.

Here is how my URL looks like:
http://www.mockaroo.com/api/generate.json?key=<MyKey>&schema=<SchemaName>&p1=aaa&p2=bbb

I also tried:
https://api.mockaroo.com/api/<xxx>?count=1&key=<myKey>&p1=aaa&p2=bbb

And this is the response I get:

{
"id": 1,
"p1": "error: Could not access blank value: Use || to provide a default value for blank fields.  Example: (my_field || 0) + 1",
"p2": "error: Could not access blank value: Use || to provide a default value for blank fields.  Example: (my_field || 0) + 1"

}

Why the parameters p1 and p2 are not being picked up? Any clue as to what am I missing?
I did double check on correct use of the API key and schema, but no luck…

Thanks in advance…

According to Mark Brocato:

The request_params hash is only populated when you generate data using a mock API (created via the APIs section linked in the site’s header). So for example if you created an API for /users you would call: https://my.api.mockaroo.com/users?key=(your key)&region=US.

Mark indicates that he may add this functionality to the regular data generation API as well.

Thanks for being persistent Cameron and for answering the post. I actually just pushed an update that makes request_params available for all APIs.