Udp-dtls using fingerprint

I would like to catch the udp-dtls stream of a webrtc stream. Typically this need to verify with a fingerprint. Is there any example how to establish such a udp-dtls connection with fingerprint. I try to use

mbedtls_ssl_conf_ca_cb(&conf, ca_callback, &cacert);

with the dtls_client.cpp, but somehow it don’t works…

Kindly regards,