[SOLVED] What are the correct security policy value settings to allow both RMI and JPA/Hibernate to work at the same time

I'm working on an application that requires the use of both JPA/Hibernate and RMI. Since RMI requires the use of a Security Policy to make sure that access to the network is correctly assigned I also now have to worry about the folder permissions.

I've been looking online (and here at SO) for a couple of days now trying to find a solution to this problem. Basically the problem is that for JPA/Hibernate to work I have to place the persistence.xml file in the META-INF directory, and the META-INF directory must be under the src directory of my project (which doesn't make sense to me either but it works). So that the project layout is basically:

 org.project.root
 |
 |>src
 |  |
 |  |>org.project.package
 |  |
 |  |>META-INF
 |       |
 |       |>persistence.xml
 |
 |>config
 |
 |>database
 |
 |>logs

My security policy file I've been trying to grant read access to the folder ${user.dir}${/}src${/}META-INF${/}-, however, when I try to run the application I get the error No Persistence provider for EntityManager named DERBY_ACPSTORE_CREATE. My persistence.xml file however does contain this, and it works when comment out all the RMI stuff and stop reading the security policy. So my question is how can I get my security policy file to allow me to read the persistence.xml file?

UPDATE 1

Using the suggested path information from @Vineet Reynolds I'm able to see the file's path using:

 File f = new File("META-INF/persistence.xml");
 System.out.println(f.getAbsolutePath());

However, I'm still getting this error when I'm trying to create the database.

 javax.persistence.PersistenceException: No Persistence provider for EntityManager named DERBY_ACPSTORE_CREATE
 at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:55)
      at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:33)
      at org.myproject.data.DBInit.dbInit(DBInit.java:29)
      at org.myproject.ACPStoreMainService.main(ACPStoreMainService.java:91)

My persistence.xml as I said worked fine before I started using the security policy so I know that the persistence-unit "DERBY_ACPSTORE_CREATE" is present and correct.

Update 2

Although I'm not sure what good this is since it worked when I don't use the Security Policy here's my persistence.xml contents:

 <?xml version="1.0" encoding="UTF-8"?>
 <persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"         xsi:schemaLocation="http://java.sun.com/xml/ns/persistence     http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0">
      <persistence-unit name="DERBY_ACPSTORE_CREATE">
           <provider>org.hibernate.ejb.HibernatePersistence</provider
           <class>org.myproject.data.MessageHistory</class>
           <properties>
                <property name="hibernate.connection.driver_class" 
           value="org.apache.derby.jdbc.EmbeddedDriver" />
                <property name="hibernate.dialect" value="org.hibernate.dialect.DerbyDialect" />
                <property name="hibernate.connection.url" value="jdbc:derby:database/acpstore;create=true" />
                <property name="hibernate.show_sql" value="true" />
                <property name="hibernate.format_sql" value="true" />
                <property name="use_sql_comments" value="true" />
                <property name="hibernate.hbm2ddl.auto" value="create" />
                <property name="hibernate.connection.username" value="user" />
                <property name="hibernate.connection.password" value="password" />
           </properties>
      </persistence-unit>
 </persistence>

UPDATE 3

As I mentioned in the comment to the answer from Vineet Reynolds below I've tested the persistence.xml without the security and it is now working. Then when I reinstate the security policy then I get the errors again. As such below is the contents of my security policy and how I create the security in my application:

 grant {
      permission java.lang.RuntimePermission "shutdownHooks";
      permission java.lang.RuntimePermission "readFileDescriptor";
      permission java.lang.RuntimePermission "writeFileDescriptor";
      permission java.util.PropertyPermission "user.dir", "read";
      permission java.net.SocketPermission "172.10.10.21:1024-65535", "connect, accept, resolve";
      permission java.net.SocketPermission "172.10.10.21:1-1023", "connect,resolve";
      permission java.io.FilePermission "${user.dir}${/}META-INF${/}-", "read";
      permission java.io.FilePermission "${user.dir}${/}config${/}-", "read, write, delete";
      permission java.io.FilePermission "${user.dir}${/}database${/}-", "read, write, delete";
 };

And this is what happens in my application to set the security manager

 if(System.getSecurityManager() == null)
 {
      System.setSecurityManager(new RMISecurityManager());
 }

UPDATE 4

I've found a message that I didn't notice before coming from log4j. The message is

 [main] INFO org.hibernate.ejb.Ejb3Configuration  - Could not find any META-INF/persistence.xml file in the classpath

which seems odd to me. So I listed the directories in the classpath and I found org.project.root\bin but not org.project.root. I know now that the META-INF in the runtime is located as org.project.root\META-INF, and that the classpath should point to the org.project.root so that JPA and hibernate can access find the persistence.xml. So would could it be that I need to somehow change the classpath to match this?