problem with AutoCAD type library (acad.tlb)

hi together!
does anyone know how i can send commands to extern AutoCAD
applications like 3d-render via the acad.tlb interface?
there is one way in AutoCAD 2000, with SendCommands i can send text
commands to the AutoCAD console, but this doesn't work in AutoCAD 14
and unfortunately the user can see my SendCommands inputs...
thanks a lot for helping!
Jonas