I have reproduced this behavior in DIAdem 2011 SP1, however, after testing the process in DIAdem 2012 Beta 1, it seems that the behavior has already been fixed.
If you're interested in testing it yourself to ensure that it also works on your system, you can sign up for the Beta for free at ni.com/beta. Thank you for the feedback!
Derrick Snyder
Product Manager
NI DIAdem
Derrick S. Product Manager NI DIAdem National Instruments