diff --git a/lib/client.js b/lib/client.js
index 856ecb3ad..33fd10783 100644
--- a/lib/client.js
+++ b/lib/client.js
@@ -802,15 +802,6 @@ MatrixClient.prototype.publicRooms = function(callback) {
     return this._http.request(callback, "GET", "/publicRooms");
 };
 
-/**
- * @param {module:client.callback} callback Optional.
- * @return {module:client.Promise} Resolves: TODO
- * @return {module:http-api.MatrixError} Rejects: with an error response.
- */
-MatrixClient.prototype.registerFlows = function(callback) {
-    return this._http.request(callback, "GET", "/register");
-};
-
 /**
  * @param {module:client.callback} callback Optional.
  * @return {module:client.Promise} Resolves: TODO
@@ -932,16 +923,24 @@ MatrixClient.prototype.login = function(loginType, data, callback) {
 };
 
 /**
- * @param {string} loginType
- * @param {Object} data
+ * @param {string} username
+ * @param {string} password
+ * @param {string} session_id
+ * @param {Object} auth
  * @param {module:client.callback} callback Optional.
  * @return {module:client.Promise} Resolves: TODO
  * @return {module:http-api.MatrixError} Rejects: with an error response.
  */
-MatrixClient.prototype.register = function(loginType, data, callback) {
-    data.type = loginType;
-    return this._http.authedRequest(
-        callback, "POST", "/register", undefined, data
+MatrixClient.prototype.register = function(username, password, session_id, auth, callback) {
+    if (auth === undefined) auth = {};
+    auth.session = session_id;
+    return this._http.requestWithPrefix(
+        callback, "POST", "/register", undefined,
+        {
+            username: username,
+            password: password,
+            auth: auth
+        }, httpApi.PREFIX_V2_ALPHA
     );
 };
 
diff --git a/lib/http-api.js b/lib/http-api.js
index 5c8b7b0d5..3aa553157 100644
--- a/lib/http-api.js
+++ b/lib/http-api.js
@@ -352,6 +352,7 @@ var requestCallback = function(defer, userDefinedCallback, onlyData) {
     return function(err, response, body) {
         if (!err && response.statusCode >= 400) {
             err = new module.exports.MatrixError(body);
+            err.httpStatus = response.statusCode;
         }
 
         if (err) {