Java EE (Java Enterprise Edition) General Discussion

hello

In my pc i have installed the 1.6_10 jdk.
i must to compile, for generate one war for one 5.0 tomcat that runs into one 1.4 jdk, my classes.
for this pourpose i make this into one build.xml file:
<javac destdir="${entornoBase}/${classes}" includes="**/${path}/${filej}.*,**/${filej}.*" excludes="**/*EJB/*.*,**/**ejb/**/*.*" classpath="${classpath}" optimize="on" deprecation="on" source="1.4" target="1.6">
<src path="${entornoBase}/${fuentes}"/>
</javac>

but using the options:
optimize="on" deprecation="on" source="1.4" target="1.6">
always appears into my tomcat this:
2008-12-26 17:42:07,483 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] ERROR org.apache.catalina.startup.HostConfig - Exception while expanding web application archive Goikogane.war
java.lang.UnsupportedClassVersionError: com/goikogane/servlets/GOIKOInitServlet (Unsupported major.minor version 50.0)
at java.lang.ClassLoader.defineClass0(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:539)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:123)
at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:1634)

can you help me for compiling the classes for make it compatible with the 1.4 jdk?

thanks