[XeTeX] Fontspec question win32

[jropers@freesurf.fr]

Hello,

I have a question relating to Fonspec: is it possible to specify which 
font should be used as the italic/bold/sc form when the name itself is 
not fully explicit ? As an example to clarify the question how to 
specify one of the 2 fonts as the italic form :
-Scala Sans:style=Regular Italic
-Scala Sans:style=Light Italic
(info obtained with fc-list under win32, type 1 fonts)

Thanks,

Jacques