Hi Metin,

>Right now my workaround is to set the CPlane to a new object orientation every time, and
> switch to a front/side/top view to get the rotate/scale gadget around my selection. But
> that's too elaborate.

Check out here for a script that will set the cplane to the 3D view direction, that might help to ease this process somewhat:
http://moi3d.com/forum/index.php?webtag=MOI&msg=2599.4

- Michael