I can surely confirm that this works:
AMD R9 290x
Windows 7 64
This is what I did and I hope this helps someone with the same problems/system specs:
1) I uninstalled all AMD drivers and shutdown my machine
2) I replaced the new card with the old HD4890 that I had working before and powered up the system.
3) I installed the Catalyst 13.9 legacy driver and reboot.
4) I installed Soft-15KHZ's all resolutions in all available cards, just to Uninstall everything right after that.
5) I uninstalled all AMD drivers again and shutdown.
6) I replaced the old card with the R9 290x and powered the system.
7) I installed Catalyst 14.4 (newer drivers might be the cuplrit for ir not to work before, not sure. This one works though)
9) I ran Soft-15KHZ and I got 5 popups, one after the other saying "For pre-X1000 series Radeon cards Catalyst 6.5 is recommended.", which makes no sense in this case, since this card wasn't supported by that driver, so I just kept clicking ok.
10) Soft-15KHZ's interface shows up! The catch is that instead of listing the correct card's name, it shows a list of 5 available cards, all listed as "Standard VGA Graphics ..."
11) I added all resolutions to all of the 5 listed cards and reboot.
12) Back to windows I ran Quickres and BOOM! All resolutions are now listed!!!
I' m pretty sure some of those steps are probably not even necessary, but if nothing works for you, give it a go.