problem converting png with alpha to web

[tsahia]

test:
using latest webp from today (11 july 2012 download from http://git.chromium.org/gitweb/?p=webm/libwebp.git) that supports alpha in webp and png.
take a png image with alpha, convert to webp and back. check if the alpha is there

using ImageMagic convert this works ok.
but when i wrote my own code using Magic++ it used to work in version 6.7.6-5 but in newer version (i tested 6.7.7-7 and 6.7.8-2) i lose the alpha channel.

Thankls

[tsahia]

correction, it's not only magic++ convert also does not work, i'll try to move this thread to bugs or post a new one.