[Freeswitch-users] Write wav files at 48000hz and I need 8000hz

Hello, I am working with FS 1.8 and everything goes well enough so far. We record all the inbound and outbound calls. The inbound calls are recorded as wav 8000hz sample rate. But the calls outbound are recorded as 48000hz sample rate as wav files, the question is, is it a config to set the default or force the recording to be saved as 8000hz always? I use verto and sip clients, the telephone-event and the sample from codecs is 8000hz so I dont understand how to achieve this. Any help would be appreciate it. Thanks JNF