Hi,
Actually it is not advisable to give post dated checks from SAP as
1. It affects agewise reporting.
2. It affects vendor Open item list as you need to change the payment terms.
In case you want to give post dated checks, you can do following
1. You can give check manually and update the same through FCH5 (Create check information).
2. In case you want to give PDC through F110 then change the posting date to the PDC date.
Pre-requisites
1. Change payment terms in document.
2. Remove payment block from document.
Important note
Please be very careful in case you are giving this process to client and warn him about the consequences as on later date in case agewise goes wrong there can be a management issue.
Regards,
Tejas