Testing RESTful Web Services: try to send an Array

Hallo,

I want to send an Array with the REST Client. 

I have this Array: 

$postData =
    ['start' => ['rot', 'gelb', 'blau'], 'zweites' => ['erster' => 'roter', 'zweiter' => 'gelber', 'blauer']];

How can I put this Array in the field RequestParameters from the REST Client?

I have tryed to urlencode or to serialize... it doesn't work.

I can make this: $postDataQuery = http_build_query($postData)

I can put the $postDataQuery into the RequestBody as "Text" field.

So I will get the POST RAW data - But this is not what I want.

The Problem: I make a curl-Request (with $postDataQuery) - and then I get the POST - data - how can I simulate this?

Or is this not possible?

Thank you!