title: Passing property group value from one MsBuild task to another
body: <p>How do I keep values defined in one build target alive in other targert? If PropertyGroup is not the write MsBuild entity I should use here, what is? ReleaseDir is printed ok in "Package" target, but is empty in "DoPackage"</p>
  
  <pre><code>&lt;Target Name="Package"&gt;
    &lt;PropertyGroup&gt;
      &lt;ReleasesDir&gt;c:\tmp&lt;/ReleasesDirBase&gt;
    &lt;/PropertyGroup&gt;
    &lt;Message Text="$(ReleaseDir)"/&gt;
    &lt;CallTarget Targets="DoPackage" Condition="!Exists('$(ReleaseDir)')"/&gt;
  &lt;/Target&gt;
  
  &lt;!-- Do the acutal packaging --&gt;
  &lt;Target Name="DoPackage"&gt;
    &lt;Message Text="Creating package in '$(ReleaseDir)'"/&gt;
    &lt;Error Condition="'$(ReleaseDir)' == ''" Text="No ReleaseDir defined"/&gt;
    &lt;MakeDir Directories="$(ReleaseDir)"/&gt;
    ...
  &lt;/Target&gt;
  </code></pre>