[Freeswitch-biz] Tier 1's and/or ITSP's and SRTP

Hey folks. I have a client who is looking for (preferrably) a Tier 1 provider that can provide SRTP (TLS mode) on SIP trunking. The alternative would be an ITSP that can provide support for SRTP, but it has to be all the way to the point of injection into the PSTN. My client has HIPAA considerations, so this is a deal breaking issue, as it turned out to be with XO. The client needs somewhere on the order of 48-52 SIP trunks. Please let me know if you have any pointers/referrals. -Yossi