How to manage exception while using Container Managed Transactions?

Issue

• Following is the sample EJB code;

...
        try{
            System.out.println("**************  trying to persist  **************");
            _em.persist(atmAdmin);
        }
        catch(Exception e){
            System.out.println("#####################  could not persist to database  ###################");
            e.printStackTrace();
        }
...

• Below is the datasource details;

...
<datasources>
  <local-tx-datasource>
    <jndi-name>TempDB</jndi-name>
    <use-java-context>true</use-java-context> 
    <connection-url>jdbc:sqlserver://127.0.0.1:1433;DatabaseName=Temp</connection-url>
    <driver-class>com.microsoft.sqlserver.jdbc.SQLServerDriver</driver-class>
    <user-name>test</user-name>
    <password>12345678</password>
    <min-pool-size>10</min-pool-size>
    <max-pool-size>50</max-pool-size>
    <metadata>
        <type-mapping>MS SQLSERVER2000</type-mapping>
    </metadata>
  </local-tx-datasource>
...

• When the database is down, I don't get the exception in my code and the exception is logged to the server.log probably by hibernate but only after the transaction is committed.

• How I can control the exception in my code?