aws-s3-proxy fails to proxy encrypted objects from encrypted buckets

[calve]

Hi,

it looks like aws-s3-proxy cannot proxy encrypted objets on a bucket with Server Side Encryption (SSE) configured. The browser shows the following error from S3

<Error>
<Code>InvalidArgument</Code>
<Message>
Requests specifying Server Side Encryption with AWS KMS managed keys require AWS Signature Version 4.
</Message>
<ArgumentName>Authorization</ArgumentName>
<ArgumentValue>null</ArgumentValue>
<RequestId>3431EC777CCE0481</RequestId>
<HostId>
KB4eUwlajOnuFcHuxFmpGoCy3s+kftrtdlB3JrALmCg9qEw9LvkHmtSkvOk2xhIZmgSOfOzYgrM=
</HostId>
</Error>

Looking at the documentation, AWS Signature Version 4 should be managed by the golang SDK. Am I missing something ?