[itsm] Date input in configuration items

Hi, I create a new configuration item class, in which I have several date fields. In these fields the dates are entered selecting an option through a combo box. The point is that range of years I can choose goes from 2000 to 2020, and I need to enter date before 2000. Anyone knows if it's possible to extend the range of the years to enter? Thanks. Regards. Daniel. _________________________________________________________________