Posting multidimensional array with PHP and CURL

I'm having trouble posting form data via CURL to a receiving PHP script located on a different host.

I get an Array to string conversion error

This is print_r of the array I'm posting:

Array
(
    [name] => Array
    (
        [0] => Jason
        [1] => Mary
        [2] => Lucy
    )
    [id] => 12
    [status] => local
    [file] => @/test.txt
)

This is the line the error occurs on:

curl_setopt($this->ch, CURLOPT_POSTFIELDS, $post);

The third argument must be an array because I need the Content-Type header to be set to multipart/form-data as I am sending a file via this same array, therefore I cannot convert the array to a query string or use http_build_query().

Also I do not have access to the code on the receiving host so I cannot serialize and unserialize the array.

I'm assuming that the value of the name key being an array is the cause for this error, I'm also assuming that CURLOPT_POSTFIELDS doesn't support multidimensional arrays. Is there any other way around this or am I doomed?

Thanks in advance!