[Zope] force bobobase_modification_time

Is it possible to control the bobobase_modification_time at all? When moving objects but actually recreating them through a little script they all get the natural bobobase_modifiaction_time which is that of the creation date. I was _hoping_ to do something like this: object.bobobase_modification_time.set('2001/10/09') ...or... object.bobobase_modification_time.set(ZopeTime('2001/10/09')) ...but this syntax obviously doesn't work. Cheers, Peter