[XeTeX] letter spacing

[ricardroca at gmail.com]

Hi,

letterspacing has always been a difficult work for TeX, and with classic TeX 
the right way was to build a new tfm with 'letterspaced' metrics (fontinst 
and other programs did that), because macro packages (like 'soul' for LaTeX) 
were somewhat limited.

As XeTeX doesn't work ('natively') with tfm's, is there a way to play with 
letterspacing directly on the \font command? (I know the OpenType 'cpsp' 
feature, but it's only a special case.)

Thanks a lot

Ricard