The requirement for a task definition for Windows is to leave the network mode as default.  It is not possible to do that currently with current plugin.  It forces: none,host,awsvpc or bridge.  Default is required for Windows containers.

See here: https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task_definition_parameters.html#network_mode

Excerpt: Docker for Windows uses a different network mode (known as NAT) than Docker for Linux. When you register a task definition with Windows containers, you must not specify a network mode. If you use the AWS Management Console to register a task definition with Windows containers, you must choose the default network mode.