A bit late in bringing this up, but...
Freshly reformatted the rig (Vista, FSX/Acceleration, Q6600 2.4Ghz, 4Gb RAM, 8600GT 512mb) and thought I'd have another crack at using DX10 and playing around with the HDR and bloom...
FPS improved greatly over DX9c but... The AA is barely there
Applied all of my base-level presets with the Nvidia control panel, then shagged around with Nhancer all afternoon and got some ok-ish AA but it's miles below the standard I had in FSX running DX9c or even FS9.
Tried every combination of in-sim and Nhancer setting I could find but nothing improved it... I did swap back to DX9c and on the high-end AA settings, Nhancer was certainly doing it's job there - just not with DX10
Anybody else hit this one before?