calculating date via objectmethod and using in latest end / start of workitem

[Giesinger Marc]

hello all
 
i have a small prop which maybe can be solved here ...
i use a method of an object to calculate a date (depending on
"workingsdays") and pass it to an WF definition via an parameter defined
like tab. QMEL / field ERDAT for example or any other date field
 
the prop is, when i use this term for the latest start or latest end
condition on a workitem the WF stopps and the item is not created
 
no errormessage nothing just stopps (like waiting on godot)
when i remove the term the WF works fine again ?!?
 
maybe a problem with the format of the parameter ? but which field
definition should i use instead ?
 
please help
 
thanks Marc