How can I point from an Eclipse target-platform.target file to my $HOME/.eclipse/org.eclipse.platform_$VERSION/plugins?

Question

Bioclipse uses a custom target-platform.target which looks like:

<?xml version="1.0" encoding="UTF-8"?>
<?pde version="3.2"?>

<target name="Spring-osgi-1.0.2">

   <location useDefault="true"/>

   <content useAllPlugins="true">
      <plugins>
      </plugins>
      <features>
      </features>
      <extraLocations>
         <location path="${project_loc}/spring-osgi-1.0.2/dist"/>
         <location path="${project_loc}/libs"/>
         <location path="${project_loc}/spring-osgi-1.0.2/lib"/>
         <location path="${eclipse_home}/plugins"/>
      </extraLocations>
   </content>

</target>

Now, I am working on an Ubuntu platform, with the Eclipse 3.5 .deb that comes with 9.10. That all works fine, and Features I download end up in a private folder:

/home/egonw/.eclipse/org.eclipse.platform_3.5.0_155965261/plugins

Now, this target-platform.target file is actually in our source repository (Bioclipse is EPL), so I would like to add something like this:

<location path="/home/egonw/.eclipse/org.eclipse.platform_3.5.0_155965261/plugins" type="Directory"/>

but then system independent, using a variable used in the other location lines in the original target-platform file. Something like:

<location path="@{user.home}/.eclipse/@{eclipse_platform_version}/plugins" type="Directory"/>

But I could not find the proper variables name to use... what should I make that line look like to make it independent from the eclipse version and the actual path of my home folder?