[Plone-UI] problem with a custom stylesheet not rendering

[Lucia Colombo]

Hi all,
I am developing a custom product which will also apply a custom footer to 
the page, with its own stylesheet.
I installed the stylesheet in the product installation script, and the 
stylesheet shows in portal_css registry, and it gets loaded in the 
main_template, but the relevant styles don't get applied. If I copy the 
styles defined in the custom stylesheet in ploneCustom.ccs, they do.

What am I missing? I would actually like the stylesheet to be a part of the 
product, so that I don't need to make other customizations any time I use 
the product.

thanks&bye
Lucia