[XeTeX] Why do I get small caps/random font?

[Mojca Miklavec]

Hello,

I'm a bit confused. I installed the whole Latin Modern font family,
but when I try to use
    \font\A='Latin Modern Roman' \A
I get lmroman10-capsregular.otf.

And if I use
    \font\A='Latin Modern Roman/B' \A
the font lmroman5-bold.otf is used.

The behaviour seems completely random. Should I only be more precise
when specifying the font names or is there a way to influence that
randomness?

Thanks a lot for any hints,
    Mojca Miklavec