How to create a mail subsystem from scratch with the CLI in JBoss EAP 6?

Issue

• When trying to add a mail subsystem to a new profile in EAP 6 from the CLI, the following results:

./subsystem=mail:add()
{
    "outcome" => "failed",
    "failure-description" => {"domain-failure-description" => "JBAS014677: Failed to persist configuration change: JBAS014675: Failed to marshal configuration"},
    "rolled-back" => true
}