use defined props so that we are only searching for and modifying once

build.properties

@@ -235,7 +235,7 @@ sai.simserver.dir=${examples.dir}/sai/simserver
 examples.spec.x3d.java.dir=${examples.dir}/spec/x3d/java
 
 xj3d.version=Version
-xj3d.version.number=2.2
+xj3d.version.number=${product.version.major}.${product.version.level}
 xj3d.version.file=${src.java.dir}/org/web3d/util/${xj3d.version}.java
 
 browser.class=${browser.classes.dir}/xj3d/browser/Xj3DBrowser.class