Hi groovyguy,
thanks for the offer! I might come back to it.
It seams my way of explanation is really confusing to everybody else than me :P. My main goal is that the date is random and successively increasing. If I understand correctly your suggestion would be a way to count upwards from a given date.
For that I would have to create a list of dates at the beginning of the test step and than iterate over that list or I would have to generate the date on every cycle for which I would have to store the last date i.e. in a property, so I can access it on the next cycle and increase it by a random amount.