Automatically cr. block Sales Order once they reach within the Cr. Horizon

How to automatically credit block Sales order made outside the Cr. Horizon, once they reach into the Cr. horizon.

I have tried testing the same through Program RVKRED08, but it works for some orders if the Cr. horizon is maintained for 60days.

But does not block if the Cr. horizon is maintained for 30days.

Thanks in Advance