DTMF out-of-band or inband or SIP-INFO?

Hello,
we have a connection with Cisco UCCX with which we can not establish a call. We're using TLS and sRTP in this SA. So an INVITE we are sending to Cisco is:

INVITE sip:12345@x.x.x.12:5062;user=phone;transport=tls SIP/2.0
Via: SIP/2.0/TLS x.x.x.204:5062;branch=z9hG4bK45cr8v0070h54peu5g80.1
Call-ID: BW125455020030921965152606@10.254.235.24
From: <sip:+34671012345@176.104.64.191;user=phone>;tag=261272374-1630666495020-
To: "Aplicacion Aplicacion"<sip:12345@conecta.orange.es;user=phone>
CSeq: 363203095 INVITE
Accept: application/dtmf-relay,application/media_control+xml,application/sdp,multipart/mixed
Allow: ACK,BYE,CANCEL,INFO,INVITE,OPTIONS,PRACK,REFER,NOTIFY,UPDATE
Contact: <sip:x.x.x.204:5062;Hpt=8e78_16;CxtId=4;TRC=ffffffff-ffffffff;transport=tls>
Max-Forwards: 68
Supported: 
P-Asserted-Identity: <sip:+34671012345@176.104.64.191;user=phone>
Privacy: none
Recv-Info: x-broadworks-client-session-info
Content-Length: 331
Content-Type: application/sdp

v=0
o=- 259070397 1 IN IP4 x.x.x.204
s=SBC call
c=IN IP4 x.x.x.204
t=0 0
m=audio 12698 RTP/SAVP 8 18 97
a=rtpmap:8 PCMA/8000
a=rtpmap:18 G729/8000
a=fmtp:18 annexb=yes
a=rtpmap:97 telephone-event/8000
a=fmtp:97 0-15
a=ptime:20
a=crypto:1 AES_CM_128_HMAC_SHA1_80 inline:y5gz53bivZkCxRHf0QZltmXFIYMbIbip59J0XGes

200 OK on this INVITE comes without a=crypto... line, because Cisco is claiming that 
we're sending DTMF inband and not out-of band.
 a=rtpmap:97 telephone-event/8000 tells me that it is RFC 2833 and it is out-of-band. Am I right?
I would also like to change RFC2833 with SIP-INFO so in a codec-policy I put telephone-event:no and
rrfc2833-mode in dual? 

Thanks for your