I know these limitations are annoying, but unfortunately they are inherited from SDL, the portable graphics library WME Lite is using.
While both of these features are easy to achieve on 3D accelerated hardware, SDL keeps compatibility with non-accelerated systems and for that reasons those features were never added.
The mirroring could be faked for the price of keeping multiple copies of the image in memory, but there's no feasible way of providing smooth rotation without hardware support.