How to enable On Screen Keybord (OSK.exe) When a texbox is highlighted

I wrote a VB 6 application for Windows 7 touch screen, how can I call the On Screen Keyboard (OSK.exe) when user point on the text box?

With windows 7 and Windows touch it will not have any problem, but the problem is the Windows touc开发者_JS百科h pack cannot be installed into the touch screen that does not support double simultaneous touch.

We have an industrial machinery software we develop that runs on touchscreen. We just have our own form that has every key on it that when closed returns the value back to the textbox.