VI prototype not showing with waveform input

I have two VIs, one acquiring waveform data, the other using that waveform data to calculate some characteristics.

When I use a waveform cluster as output of the first and input of the second VI, the first VI is loaded correctly into TestStand; for the second VI I get the error that the parameters do not match the controls of the VI. Actually, no parameters are shown at all in TestStand 2012 and the prototype is never updated.

When I change the signal representation to an X and Y value array, then it works.

What can be the problem here?

Peter