Error importing VirtualKeyboard in a custom build

Hello everyone!
I am working on QGroundControl customization. I import VirtualKeyboard in PlanView.qml using:

import QtQuick.VirtualKeyboard  2.15

I have also added:

qputenv("QT_IM_MODULE", QByteArray("qtvirtualkeyboard"))

at top of main function in main.cc. But when running application I get error:

module "QtQuick.VirtualKeyboard" is not installed

Does anyone know how to fix it?
Thanks