Here is a draft of the mail I'd like to send to Dean Edwards, the creator of the cssQuery library. If it's ok with you, I will then send it.
first of all, thanks for your work on cssQuery.
I'm coming to you about your cssQuery library. As you know, it is already used by the Selenium application which allows functional testing on websites. I am myself using it, and I'm working on an Apache project which is called OFBiz. As you may know, only work licensed under the Apache2 license can be included in those projects, or any code with a compatible licence. There is then a problem with Selenium (for the Apache Fundation) as it is using your library, you can see it there : http://www.apache.org/legal/resolved.html#category-x
It's then why I come to you, to know if it would be possible to double-licensing your work, or change the license of the cssQuery library to one of the licenses compatible with the Apache Fundation guidelines : http://www.apache.org/legal/resolved.html#category-a
Thanks a lot for considerating this request, and I'm ready to discuss more about this with you if needed.