When you set timestampedVersion to the true value, the version of the generated package will be completed by a a timestamp. The aim is to keep the pom unmodified while you can perform several deployments without clashes.
if you have a pom using dar packaging, use mvn package deployit:import
Use the special tags
Yes, it does since 3.6.4. Just add your server to the settings.xml and it will be used for Deployit authentication. Make sure to use only username and password tags.
The default server id is 'deployit-credentials'. It can be modified using the server tag in the plugin configuration.
Passwords can be encrypted if needed Password Encryption