LoadTest fails

I have created a Test Property (Counter) on the UserGet TestCase.
I the Groovy Script, I get the Counter and increase it with 1
And then transfer it to the Test Property.
That works just fine when I run it. The Counter increases just fine for every run.
But when I use the LoadTest, it ignore the counting

I'm unsure it's the right way I'm doing it.

What I basically want is the following :

Loop with counter from 1 to x
{
  TestRequest (CreateUser param email = "testuser(counter)@g.dk"
  TestRequest (ActivateUser param = TestRequest CreateUser.email
}

What to do ? Any suggestions are welcome !

Thanks
Jan