Test successful with VS Testrunner but fails with SmartRunner. Why?

The foillowing test is successful when I run it with Visual Studio Testrunner but fails when I run it with SmartRunner even if I do not mocking at all. I just use the TypeMock Testrunner. That's all.

[TestMethod]
[TestCategory("IntegrationTest")]
public void ATest()
{
  // I know that is not a test that makes any sense. It's just some code 
  // to illustrate the issue that I have with SmartRunner.

  using (new Impersonator(new NetworkCredential("username", "password", "domain.local")))
  {
    using (DirectoryEntry de = new DirectoryEntry("LDAP://domain.local"))
    {
      SearchResult adSearchResult = null;
      using (DirectorySearcher adSearch = new DirectorySearcher(de))
      {
        adSearch.Filter = string.Format("(sAMAccountName={0})", "MockTestUser");
        adSearchResult = adSearch.FindOne();
      }
    }
  }
}

The Impersonator is using native method LogonUser from advapi32.dll to perform the impersonation.

Result with VS Testrunner: 

Result with SmartRunner:

So question is why does this "test" fail when i use it with SmartRunner. Is there something I can do to get it running?