[pstricks] How to draw something like \psarc, but a piece of ellipse?

[Сторожев Максим]

Well, almost the same question, I asked before. May be some day I say what I
need it for :-) My program is in the developvent stage now.

So, \psarc(0,0){1}{0}{90} draw a piece of circle with radius 1 with center
0,0 and so on. But how to draw a piece of ellipse like this:
\psarcXXX(0,0){X-radius}{Y-radius}{Starting Angle}{Ending Angle}

Well, it deals with mapping from another graphical format to pstricks one.

Thanks you.

Maxim