RMI SybTimestamp Exception

Dear OW2 Team

We are facing the below RMI exception, When running JOnAS 4.8.4 and Tomcat
5.5.31 in two separate platforms.

We are using Sybase 15 Database and jconn3.jar JDBC driver .

The class “SybTimestamp” in jconn3.jar located under (JONAS_HOME/lib/ext/)
is available but when an RMI request is done from Tomcat the below  exception
is generated.  

Kindly advice for a solution to solve the problem, Note that putting jconn3.jar
JDBC driver under (TOMCAT_HOME/common/lib) is a successful work around! But we
are searching to solve the below using the Best Practice Solution.

java.rmi.UnmarshalException: ClassNotFoundException unmarshalling
returnjava.lang.ClassNotFoundException: com.sybase.jdbc3.tds.SybTimestamp (no
security manager: RMI class loader disabled)
      at
org.objectweb.carol.rmi.jrmp.server.JUnicastRef.performRemoteCall(JUnicastRef.java:211)
      at
org.objectweb.carol.rmi.jrmp.server.JUnicastRef.invoke(JUnicastRef.java:158)
      at
org.objectweb.jonas_gen.administration.JOnASAdministrationEJB_202388217Remote_Stub.getCreatedAdminUser(Unknown
Source)
      at
com.path.connectadmin.processes.LoginProcess.doPost(LoginProcess.java:64)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:763)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
      at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
      at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
      at
com.path.connectadmin.common.ValidationFilter.doFilter(ValidationFilter.java:15)
      at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
      at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
      at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
      at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
      at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
      at
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
      at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
      at
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
      at
org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:843)
      at
org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:679)
      at
org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1293)
      at java.lang.Thread.run(Thread.java:595)

Thanks in Advance