To definitively help you, we'd have to see some code as the pseudo-code you posted above doesn't really make sense. It's not clear where your beginscene, clear calls, endscene and presents occur with respect to each other.
EDIT: I made an error in the code I posted above with respect to setting the rectangles for the viewport and presentation. Don't know if that messed you up. Apologies.
lastly, the framework presents the image
It sounds like you're presenting the backbuffer just once. That's a bit more complicated than the simple sequence I posted above, which is intended to be straight forward.
Repeating what I posted above:
1. Set the viewport to one-half of the backbuffer.
2. Clear, BeginScene, draw, Endscene
3. Present one-half of the backbuffer to one-half of the client area of the window.
Repeat for the other half of the backbuffer and client area.