diff --git a/src/lib/getcredentialsjob.h b/src/lib/getcredentialsjob.h
--- a/src/lib/getcredentialsjob.h
+++ b/src/lib/getcredentialsjob.h
@@ -60,6 +60,26 @@
     GetCredentialsJob(const Accounts::AccountId &id, const QString &authMethod = QString(), const QString &authMechanism = QString(), QObject *parent = 0);
 
     /**
+     * This version of the constructor allow passing specific auth method and mechanism
+     * for which we want the credentials as well as additional custom parameters for the
+     * authentication.
+     *
+     * For example some account has OAuth token and username-password credentials,
+     * by setting both method and mechanism to "password", only the password will be
+     * retrieved. Otherwise it depends on the passed serviceType - if there's no serviceType
+     * set, it will use the default service for the given AccountId and will obtain
+     * the credentials needed for that service
+     *
+     * @param id AccountId for which the credentials will be obtained
+     * @param authMethod Auth method for which the credentials will be obtained
+     * @param authMechanism Auth mechanism for which the credentials will be obtained
+     * @param parameters Dictionary with additional parameters to be passed to the authentication
+     *                   service.
+     */
+    GetCredentialsJob(const Accounts::AccountId &id, const QString &authMethod = QString(), const QString &authMechanism = QString(),
+                      const QVariantMap &parameters = QVariantMap(), QObject *parent = 0);
+
+    /**
      * Starts the credentials job
      */
     virtual void start();
diff --git a/src/lib/getcredentialsjob.cpp b/src/lib/getcredentialsjob.cpp
--- a/src/lib/getcredentialsjob.cpp
+++ b/src/lib/getcredentialsjob.cpp
@@ -70,7 +70,7 @@
     Accounts::AccountService *service = new Accounts::AccountService(acc, manager->service(serviceType), q);
 
     Accounts::AuthData serviceAuthData = service->authData();
-    authData = serviceAuthData.parameters();
+    authData.unite(serviceAuthData.parameters());
     SignOn::Identity *identity = SignOn::Identity::existingIdentity(acc->credentialsId(), q);
 
     if (!identity) {
@@ -81,7 +81,9 @@
         return;
     }
 
-    authData["AccountUsername"] = acc->value(QLatin1String("username")).toString();
+    if (!authData.contains("AccountUsername")) {
+        authData["AccountUsername"] = acc->value(QLatin1String("username")).toString();
+    }
     QPointer<SignOn::AuthSession> authSession = identity->createSession(authMethod.isEmpty() ? serviceAuthData.method() : authMethod);
     if (!authSession) {
         qWarning() << "Unable to create auth session for" << authMethod << serviceAuthData.method();
@@ -105,7 +107,7 @@
                 q->emitResult();
             });
 
-    authSession->process(serviceAuthData.parameters(), authMechanism.isEmpty() ? serviceAuthData.mechanism() : authMechanism);
+    authSession->process(authData, authMechanism.isEmpty() ? serviceAuthData.mechanism() : authMechanism);
 }
 
 GetCredentialsJob::GetCredentialsJob(const Accounts::AccountId &id, QObject *parent)
@@ -131,6 +133,20 @@
     d->serviceType = QString();
 }
 
+GetCredentialsJob::GetCredentialsJob(const Accounts::AccountId &id, const QString &authMethod, const QString &authMechanism,
+                                     const QVariantMap &parameters, QObject *parent)
+    : KJob(parent)
+    , d(new Private(this))
+{
+    d->id = id;
+    d->manager = KAccounts::accountsManager();
+    d->authMechanism = authMechanism;
+    d->authMethod = authMethod;
+    d->repeatedTries = 0;
+    d->serviceType = QString();
+    d->authData = parameters;
+}
+
 void GetCredentialsJob::start()
 {
     QMetaObject::invokeMethod(this, "getCredentials", Qt::QueuedConnection);