Image Magick and .ICO files

[Marcelo Magno T. Sales]

Hi, people

I can convert .ICO files to .PNG files with convert or mogrify with no 
problems. Even if there are multiple images in the .ICO files, multiple .PNG 
files are generated, one for each image.
However, I cant do it the other way. When I try to convert .PNG to .ICO, 
an .ICO file is generated, but it seems to be corrupted. Besides, how do I 
create an ICO file from several PNG files (several sizes for the same icon)?

Thanks,

Marcelo