[XeTeX] Arno conundrum

[Stephen Moye]

I'm using XeTeX. I am also trying out Adobe's (Robert Slimbach) new font, Arno. Using XeTeX and writing:

\font\x="Arno Pro Light 36pt:+smcp" \x

works, but 

\font\x="Arno Pro Light 36pt:+onum" \x

does not. Before I get too involved in this, is it possible that some font features have been 'turned off' in this 'beta'? I took a quick look in FontLab and the features (and the classes they call) seem to be defined and populated...

Any insights?

SGM