SCP plugin should support public key authentication

At the configuration of the SCP-Plugin (at Hudson System configuration)the
message "Can't connect to server" is shown - but all given parameters are correct.
The connection via shell SCP is working fine.

If the build is done ignoring the message, the following exception is thown:
FATAL: null
java.lang.NullPointerException
at
be.certipost.hudson.plugin.SCPRepositoryPublisher.perform(SCPRepositoryPublisher.java:85)
at
hudson.tasks.BuildStepCompatibilityLayer.perform(BuildStepCompatibilityLayer.java:33)
at
hudson.model.AbstractBuild$AbstractRunner.performAllBuildStep(AbstractBuild.java:273)
at
hudson.model.AbstractBuild$AbstractRunner.performAllBuildStep(AbstractBuild.java:261)
at hudson.model.Build$RunnerImpl.post2(Build.java:136)
at hudson.model.AbstractBuild$AbstractRunner.post(AbstractBuild.java:246)
at hudson.model.Run.run(Run.java:677)
at hudson.model.Build.run(Build.java:101)
at hudson.model.ResourceController.execute(ResourceController.java:70)
at hudson.model.Executor.run(Executor.java:65)

SCP-Plugin version: scp — ver.1.3
Running on jboss-4.2.2.GA
OS: Ubuntu
JRE 1.6.0-b105