how to purchase software maintenance from endor

Hi,

Our company purchases software from vendors,  as part of the purchase we also purchase maintenance/support for that software.

we need to document the start and end date of the support we are eleigibel to receive from the vendor and be able to renew the maintenance every year.

Any idea how to implement such a scenario? is there any designated module or feature integrated with purchasing that supports handling maintenance po/contract against vendor?

Thanks

Gal