JBoss 5.0.0Beta2 datasource meta data problem

I download and installed JBoss 5.0.0Beta a day ago but I keep getting the following error:

23:03:41,609 ERROR [AbstractKernelController] Error installing to Start: name=jboss.ejb:persistencePolicy=database,service=EJBTimerService state=Create mode=Manual requiredState=Installed
java.lang.IllegalStateException: Cannot find datasource meta data: jboss.jdbc:datasource=DefaultDS,service=metadata

at org.jboss.ejb.txtimer.GeneralPurposeDatabasePersistencePlugin.init(GeneralPurposeDatabasePersistencePlugin.java:104)
at org.jboss.ejb.txtimer.DatabasePersistencePolicy.startService(DatabasePersistencePolicy.java:83)

I have left every settings except the following changes:

Replace lib\hsqldb.jar and lib\hsqldb-plugin.jar with mysql-connector library
Replace deploy\hsqldb-ds.xml with deploy\mysql-ds.xml

In my mysql-ds.xml, I have (truncated):

<datasources>
 <local-tx-datasource>
 <jndi-name>DefaultDS</jndi-name>
 <connection-url>jdbc:mysql://localhost:3306/odmsdb</connection-url>
 <driver-class>com.mysql.jdbc.Driver</driver-class>
 <user-name>devteam1</user-name>
 <password>devteam1</password>
 <min-pool-size>5</min-pool-size>
 <max-pool-size>20</max-pool-size>
 :
 :
 <metadata>
 <type-mapping>mySQL</type-mapping>
 </metadata>
 </local-tx-datasource>
</datasources>

In my standardjbosscmp-jdbc.xml, I have (truncated):

<jbosscmp-jdbc>
 <defaults>
 <datasource>java:/DefaultDS</datasource>
 <datasource-mapping>mySQL</datasource-mapping>
 <create-table>true</create-table>
 <remove-table>false</remove-table>
 <read-only>false</read-only>
 <read-time-out>300000</read-time-out>
 <row-locking>false</row-locking>
 <pk-constraint>true</pk-constraint>
 :

These settings are the exact ones that I have been using in JBoss 4.2 0CR1. I have spent a few hours searching for solutions on the Internet to no avail--none of the suggestions helps in solving the problem. Could someone help me with the problem in JBoss 5.0.0Beta2 ?

You can assume that I am an advanced user of JBossAS and other related products.

Thanks in advance.