How-to pass variables from one plugin to another

[Enrique Gaona]

Greets,
How do I go about setting the value of a variable from 1 plugin and passing
that variable to another plugin.   If I'm being vague, here are the
details:-)   I have a custom plugin (buildtools-tag-plugins) where I set
the buildNumber instance variable to the current date and time and then I
add it to the project hashtable using
project.getProperties().put("buildNumber", builddate).  What I want to do
is pass ${buildNumber} to the maven jar/ear/war plugins  as such:
                        <manifestEntries>

<Implementation-Build>

${buildNumber}

</Implementation-Build>
                                                </manifestEntries>

In my ear and war MANIFEST files, I only get Implementation-Build: null ,
while in my jar files MANIFEST files Implementation-Build doesn't even show
up.

This is how  am invoking my build:
 mvn clean com.ibm.csdp.maven.plugins:buildtools-tag-plugins:tagbuild
-Dtagbuild.tagPrefix='CSDP_DEV_tag' antrun:run install rpm:rpm

Any help is very much appreciated.   Thanks

Enrique