Worth a try :) If it is supported, I'd change it to `application/tar`, otherwise I'll leave it as-is, but change the headers in the [RemoteApi#build](https://github.com/andreaturli/jclouds-labs/blob/master/docker/src/main/java/org/jclouds/docker/compute/features/RemoteApi.java#L259-L272) methods accordingly.