Shooting flash in Portrait Mode

[jamesino]

While recently taking some flash photography under incandescent lightbulbs with a Canon 400D Rebel XTi and the kit lens, I noticed that when I shoot in portrait mode, the picture comes out much softer and more orangish and less noticeably shot with flash. What settings would the portrait mode be shooting in? I tried simulating it by switching to Tv, Av, P and M, and mixing the WB and flash comps, but I couldnt get the nice effect the portrait mode was giving me.

 

[Mav]

can you post an example?