Sign and send an Algorand transaction in PHP?

Hi, there,
I’m trying to create, sign and send an Algorand transaction in PHP. I have obviously generated through swagger.io the relative client. However in the call REST KMD POST /v1/transaction/sign I I should send:

{
“transaction”: “…”,
“wallet_handle_token”: “…”,
“wallet_password”: “…”
}

I have the wallet_handle_token from another REST result and I have the password.

These is the code:

<?php

require_once(__DIR__ . '/vendor/autoload.php');

// Configure API key authorization: api_key
Swagger\Client\Configuration::getDefaultConfiguration()->setApiKey('X-KMD-API-Token', 'YOUR_API_KEY');
// Uncomment below to setup prefix (e.g. Bearer) for API key, if needed
// Swagger\Client\Configuration::getDefaultConfiguration()->setApiKeyPrefix('X-KMD-API-Token', 'Bearer');

$api_instance = new Swagger\Client\Api\DefaultApi();
$sign Transaction Request = ; // SignTransactionRequest | 

try {
    $result = $api_instance->signTransaction($sign Transaction Request);
    print_r($result);
} catch (Exception $e) {
    echo 'Exception when calling DefaultApi->signTransaction: ', $e->getMessage(), PHP_EOL;
}
?>

$sign Transaction Request = ??

Request is an array of Transaction?? A string? A Base64 of JSON data of a normal block Transaction?

I can’t find anything in the documentation on it. Can someone help me?

Thank you very much,
regards.

Enrico