[XeTeX] suppressing common ligatures and kerning

[Florian Grammel]

In LaTeX the command \/ suppresses common ligatures, e.g.. in  
composites like germ. Auf\/lauf.

Doing so in XeLaTeX gives me way too big space between f and l -- I  
supposed, that this is because the space added is specific to the CM- 
fonts.

The fontspec-documentation suggests putting a zero-width kern in  
between, which also works fine, apart from the fact that f and l now  
overlap each other. Adding an fl-kerning-pair to the font seems the  
right thing to do to me -- but how would I redefine the \/-command to  
work with this?

I'm looking for a way to let
x\/y
stand for
\addfontfeature{Ligatures=NoCommon}xy\addfontfeature{Ligatures=Common}

Could any of you give me a hint?


Or would there be another -- more elegant? -- solution to produce the  
right spacing?

Thanks in advance,
Florian.