Hello Marco.
I've just tested import of products via this link -
https://www.site.com/file1.csv
It works fine.
See screenshot -
http://screencast.com/t/URS9Kl9Gtt4C
Another thing - you have special format of link here - [http://user:password@URL]
In this case we need to implement support of such format.
I'll try to discuss about this suggestion with our development team before next Release.
According to our Policy, we implement a new features according to the volume of customer votes.