diff --git a/lib/call-session.js b/lib/call-session.js
index db5fb72..ac63dfb 100644
--- a/lib/call-session.js
+++ b/lib/call-session.js
@@ -133,7 +133,7 @@ class CallSession extends Emitter {
           const {uas, uac} = await this.srf.createB2BUA(this.req, this.res, uri, {
             proxy,
             passFailure,
-            proxyRequestHeaders: ['all', '-X-MS-Teams-FQDN', '-X-MS-Teams-Tenant-FQDN', '-Allow',
+            proxyRequestHeaders: ['all', '-X-MS-Teams-FQDN', '-X-MS-Teams-Tenant-FQDN', 'X-CID', '-Allow',
               '-Session-Expires', 'Min-SE'],
             proxyResponseHeaders: ['all', '-Allow'],
             headers,
diff --git a/lib/middleware.js b/lib/middleware.js
index 48c954a..c82967f 100644
--- a/lib/middleware.js
+++ b/lib/middleware.js
@@ -1,5 +1,6 @@
 const debug = require('debug')('jambonz:sbc-outbound');
 const parseUri = require('drachtio-srf').parseUri;
+const srf = require('drachtio-srf');
 const Registrar = require('jambonz-mw-registrar');
 const {selectHostPort} = require('./utils');
 
@@ -62,7 +63,8 @@ function route(opts) {
           //proxy
           const proxyAddress = selectHostPort(reg.sbcAddress, 'udp');
           logger.info(`proxying call to SBC at ${proxyAddress}`);
-          req.proxy(`sip:${proxyAddress[1]}`);
+          //req.proxy(`sip:${proxyAddress[1]}`);
+          req.srf.proxyRequest(req, `sip:${proxyAddress[1]}`);
           return;
         }
         req.locals.registration = reg;