How to return Acct-Response to any Acct-Request?

Hello, all! I use Fr 2.19 for WiMAX system. Since the system is a private network, no accouting is needed. However, the vendor of AGW told us that "However, even though AAA ignores all kinds of accounting messages according to operator’s policy, AAA should send response message for each accounting request message from ASN-GW. If the accounting response message is not received from AAA, ASN-GW will re-send the accounting request message." Actually, we only need AA and without the last A, i.e., accouting. But I need to handle for the requests. How could I do?