You can't draw text with direct screen access, but you can draw text into that bitmap you are going to render with direct screen access.
I have used this kind of code to display FPS
CFbsBitmapDevice* bitDevice = CFbsBitmapDevice::NewL(iBitmap);
CleanupStack::PushL( bitDevice );
fpsBuf.Format( KFps, iFPS);
bitGc->DrawText(fpsBuf, TPoint(10, 10));