Calling dynamically assigned shift in custom function

Hi,

I wrote PCRs to generate half-day absences in 2001 using custom function.  But this is not working for days when there is dynamically assigned shift.  While creating 2001 entry, the custom function is reading the daily shift from what is stored in infotypes and not what is generated dynamically (which is obvious).  How to rectify this?  I want that the absences should be created by custom function based on the dynamically generated shifts.  If tehre is any new solution to this apart from the custom functions, I am open.

Regards

Ankit