Identify Level of Hierarchy

[azrael]

I'm facing the following problem and haven't found any solution, so maybe someone
here can give me the key solution :

I have a report base on a cube.

One of the time dimension that shows the entry actual year
This looks like

  actual year
     Jan 2009
     Feb 2009
    ...

By reaching the end of the year the dimension tree looks like

  actual year
     2009
       Jan 2009
       Feb 2009
       ...
So the year as a number is now part of the tree (don't know why).
My problem now is that the report uses the "descendants" function to get the
month (during the year when report was developed it was descendants([actual year];1).
So in december this does not work anymore.

Has anyone a clou how to get something like :

If level_2 is filled
then
  descendants([actual year];2)
else
  descendants([actual year];1)

Haven't found any function for that.

Thanks in advance for your help.