[Swftools-common] animated gif

[Gunivortus Goos]

Hello,

I've an animated gif that has to be converted to swf.
The gif is a kind of rotating ball, the background
is transparent, to show just the rotating object
in the coloured html page.
I used gif2swf, but the transparent background got
solid filled. (white)
How can I get it, that the backgroundlayer stays
transparent?

-- 
Best regards,
 Gunivortus