Credit memo release

Dear

All,

In our business scenerio, credit memo is raised and after taking approval as release strategy is there invoicing is done after 3-4 months, at that point of time system is showing error that posting period is closed, which is a standard process but due to that we have to do it manually.

Is there any way out that system give me to do the posting without opening the peroid,be it configuration changes or any enhancement or exits.

Thanks in advance

Deepankar sengupta