Cannot select PR or PO Delivery Date past current calendar year

Where do I find the settings to extend the allowable delivery date for requisitions and purchase orders past the current calendar year? I looked at the FI period variants and it says start current fiscal year and end date is 3 years in future; but users cannot put a delivery date on an order past the current calendar year. How to I fix this? We have contracts that extend past the current calendar year and need to enter PO's for them.

thanks!

Wendy Applegren