TLS-profile for DTLS (Advanced Media Termination)

I'm trying to get Advanced Media Termination working to use SIP.JS and others against the Oracle SBC.

I set up a WebSocket server that forwards the SIP to the SBC, so far so good; however I fail to get the media stream working.

According to the logs, it fails to do the DTLS handsake:

Dec 1 22:05:34.849 [SERVICE] (1) TLSEngine:Recv: encBuf:0x46069698, encBufLen:580, decBuf:0x4607e000, decBufLen:65536
Dec 1 22:05:34.849 [SERVICE] (1) TLS Handshake: server <<< ???[length 000d]
Dec 1 22:05:34.849 [SERVICE] (1) TLS Handshake: server <<< DTLS 1.2 Handshake[length 012c], Certificate
Dec 1 22:05:34.849 [SERVICE] (1) Depth:0 Cert Subject DN:/CN=WebRTC
Dec 1 22:05:34.849 [SERVICE] (1) Cert Issuer: /CN=WebRTC
Dec 1 22:05:34.849 [SERVICE] (1) TLS (VerifyCallback): self-signed cert at depth 0, self signed subject:/CN=WebRTC, self signed issuer:/CN=WebRTC
Dec 1 22:05:34.849 [SERVICE] (1) TLS (VerifyCallback): Found trusted CA with subject dn:/CN=WebRTC, issuer dn:/CN=WebRTC
Dec 1 22:05:34.850 [SERVICE] (1) TLS (VerifyCallback): depth=0, trusted certificate hasn't been found.
Dec 1 22:05:34.850 [SERVICE] (1) TLS Handshake: server >>> ???[length