EVRC dissector is not recognizing RTP Payload Type-97 EVRC payloads

I have Wireshark 1.10.5 and it is not decoding the EVRC payload in RTP dynamic payload type 97 packets as per RFC3558. My search results seem to indicate Wireshark should automagically detect and decode this but it does not. There are no settings on the EVRC protocol preferences to instruct the dissector which RTP payload type to use. How do I get Wireshark to perform this function?