Thanks for the info!
I got a similar explanation a few days ago (http://www.behindthename.com/bb/view.php?id=3348323&board=gen
) and it seems that Smiljan - a personal name in Slovenia, Croatia and Serbia - does really come from this flower, the 'smilje' ('immortelle' in english): actually, the immortelle is also known by some other names in several languages, I think also as 'strawflower' in english.
On the webiste http://en.allexperts.com/q/Serbian-Language-3393/2008/1/names.htm
, someone also explained that "Name Smiljana (feminine form of Smiljan) has its root in a name of herb called "smilje" (English name dwarf everlast, Latin name Helichrysum arenarium). This herb is very popular in Serbian folklore - according to the tradition, it is a cure for many diseases".