Create a task with an existing custom Field

Thank you rob.
With the Data above, I get the following response:
Server Error: Oops! An unexpected error occurred while processing this request. The input may have contained something the server did not know how to handle. For more help, please contact api-support@asana.com and include the error phrase from this response.

And the custom_fields object is this:
{
“data”: {
“id”: 781306366706886,
“enum_options”: [
{
“id”: 781306366706887,
“color”: “aqua”,
“enabled”: true,
“name”: “Open”
},
{
“id”: 781306366706888,
“color”: “yellow”,
“enabled”: true,
“name”: “In progress”
},
{
“id”: 781306366706889,
“color”: “yellow-green”,
“enabled”: true,
“name”: “Closed”
}
],
“name”: “Status”,
“type”: “enum”
}
}