How to deploy over SCP with private key using Maven

Using Maven on windows, transfer over SCP, using a private key. It seems to be a very simple and documented process. But it didn't work for me.

In the settings.xml

<server>
  <id>myserver</id>
  <username>me</username>
  <privateKey>C:/data/home/.ssh/id_rsa</privateKey>
</server>

In the pom.xml

<distributionManagement>
  <repository>
    <id>myserver</id>
    <url>scp://myserver.domain.com/~me/deploy</url>
  </repository>
</distributionManagement>
<build>
  <extensions>
    <!-- Enabling the use of FTP -->
    <extension>
      <groupId>org.apache.maven.wagon</groupId>
       <artifactId>wagon-ssh</artifactId>
       <version>2.8</version>
    </extension>
  </extensions>
</build>

The expectation is, it should not come to ask me for a password to login. Also note that I do not want to use an external command to make it work uniformly across platforms. However ...

--- maven-deploy-plugin:2.7:deploy (default-deploy) @ sparksample ---
Downloading: scp://myserver.domain.com/~me/deploy/com/domain/myproject/1.0-SNAPSHOT/maven-metadata.xml 
The authenticity of host 'myserver.domain.com' can't be established.
RSA key fingerprint is 01:01:01:01:01:01:01:01:01:01:01:01:01:01:01:ff.
Are you sure you want to continue connecting? (yes/no): yes
: Password for me@myserver.domain.com: 

Not only asks it me for a password, it also forces me every time to accept the hostkey. It did however pickup the settings.xml file, as it is using the correct username to connect.

So how do I avoid it to ask me the password, and use the provided private key? Note that I was able to do this successfully with an ant scp task, using the exact same private key file.