Connecting to remote database server

I'm developing an application in a container managed environment (Java EE). Therefore, I shouldn't have to worry about handling and closing transactions. I simply inject the EntityManager:

@PersistenceContext(unitName = "WebApplication")
private EntityManager em;

And my corresponding persistence.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" xmlns="http://ift.tt/1cKbVbQ" xmlns:xsi="http://ift.tt/ra1lAU" xsi:schemaLocation="http://ift.tt/1cKbVbQ http://ift.tt/1kMb4sd">
<persistence-unit name="WebApplication" transaction-type="JTA">
    <properties>
        <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"></property>
        <property name="javax.persistence.jdbc.url" value="jdbc:mysql://link-to-my-database.us-east-1.rds.amazonaws.com:3306/TestDB"></property>
        <property name="javax.persistence.jdbc.user" value="admin"/>
        <property name="javax.persistence.jdbc.password" value="password"/>
        <property name="javax.persistence.schema-generation.database.action" value="drop-and-create"/>
        <property name="eclipselink.ddl-generation" value="drop-and-create-tables"/>
    </properties>
</persistence-unit>

However, this does not work. According to the JPA 2.0 specification, javax.persistence.jdbc.driver is "attended for use in Java SE environments." (Section 8.2.1.9; page 317). And even the jta-datasource and non-jta-datasource only "name the data source in the local environment" (Section 8.2.1.5; page 313).

Then how can I connect to a remote database server? Obviously, I can explicitly create an EntityManager but then I would be responsible for handling the transactions, then what's the point of being in a container managed environment? If it's possible to connect to a remote database server using JPA and a container managed environment, can you provide an example on how to do so?