The demographic trends you mention are why Europe only has a short time to address this problem. It is one thing to deal with a vocal 10 percent minority. It is a whole nuther thing to deal with a vocal 40 percent minority. Within 20 or 30 years, it will be too late. Steyn had a good column on the demographics in Europe, and as I recall, while the Muslims are still a small minority, their reproductive rate will diminish the gap in short order. For example, though 10 percent of France is Muslim, something like 40 or 50 percent of those under 20 are. So, in 30 years, if those people have 5 kids each while French have 1.2, France will be 50 percent Muslim, and have a majority of the young men, i.e., the people who are willing to fight about control of the country.
The demograpic of Europe revolve around the metropolitan areas. Eliminate those concentrations and things get back into proper persepctive.