Para el que le sirva encontre la solución:
DECLARE INTEGER Wow64EnableWow64FsRedirection IN kernel32.dll;
INTEGER nEnable
DECLARE INTEGER ShellExecute IN shell32.dll;
INTEGER nWinHandle, STRING cOperation, STRING cFileName, STRING cParameters, STRING cDirectory, INTEGER nShowWindow
Wow64EnableWow64FsRedirection(0)
ShellExecute(0, "open", "osk.exe", "", "", 1)
Wow64EnableWow64FsRedirection(1)