SVG rendered to an 8 bits indexed QImage ?

Hi
I can not get a QSvgRenderer to render to a eight bits indexed QImage :
after mySvgRenderer->render(myIndexedQImage) the image is the same as before the call.
As a possible workaround I tried to render to a 32bits QImage and then convert that to a 8bits QImage.
It kinda work. Kinda, because I can not get rid of antialiasing that occurred at render time.
I tried to set renderHints to 0, but it gave no better result.
Has anybody a hint about how I could proceed ?
Thanks in advance.

Laurent G.