Target Platform to have $HOME/.eclipse/$ECLIPSE/plugins ??

Bioclipse uses a custom target-platform... but since I am using the Eclipse 3.5 from Ubuntu now, extra features I download (GEF, BIRT, EMF, ...) end up in $HOME... so, I need to add a folder to the target-platform.target file... but I cannot find the variable for $HOME/.eclipse/org.eclipse.platform_3_foo_bar/plugins, such the files has things like @{eclipse_home}/plugins too...

Right now I have the below, but that clearly is not the solution:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<?pde version="3.5"?>

<target name="Spring-osgi-1.0.2">
  <locations>
    <location path="${eclipse_home}" type="Profile"/>
    <location path="${project_loc}/spring-osgi-1.0.2/dist" type="Directory"/>
    <location path="${project_loc}/libs" type="Directory"/>
    <location path="${project_loc}/spring-osgi-1.0.2/lib" type="Directory"/>
    <location path="${eclipse_home}/plugins" type="Directory"/>
    <location path="/home/egonw/.eclipse/org.eclipse.platform_3.5.0_155965261/plugins"
                 type="Directory"/>
  </locations>
</target>

What is the @{variable} I should use for user-based plugin folders?