'const' keyword in method parameter

I have my own class Class1, I register this class: qmlRegisterType<Class1>("my_uri", 1, 0, "Class1");
Than I want to call next method from QML:
Q_INVOKABLE void method1(const Class1 *param) const;
In runtime I have error:
file:///.../QmlFile1.qml:...: Error: Unknown method parameter type: const Class1*

But this method (without 'const' keyword) is working fine:
Q_INVOKABLE void method1(Class1 *param) const;