There is a sidebar app, namely Sidebar style SWKey for Android HTC HD2 to which you can use the hardware keys without you need to get your hand on them. This app is developed by XDA member jerryfan2000 and solely designed for HTC HD2.
If you are interested , you can follow the installation guide below to install the soft keys on Android HTC HD2:
Install the apk
When you click any of the 4 buttons first time(except close), you need to grant Button Savior root access. It happens only to your first ever button click.