Thanks to Patric Massing of Saarbrücken debugging to pin point that a Date (TimeStamp) parameter is parsed to a wrong SimpleDateFormat instead of TimeStamp.
Thanks, reviewed the patch I think it's lacking the implementation of Time reference - assuming Date when is Time.
Closing as Potential-Idea.
I'll leave it to for review, as he's the maintainer of the fitnesse as repository.
Please reopen if is worthy to integrate.