slur attachment tweak not working

[Kieren Richard MacMillan]

[ Mac OS X 10.3.5; Lilypond 2.3.10 via Fink ]

Hello, all --

Just wondering why my tweak isn't working any more:

slurHS = \once \override Voice.Slur #'attachment = #'(head . stem)

I looked through the docs, and it seems like this is no longer an 
option -- i.e., it has been replaced by different (meaning more and 
more flexible and probably better) options that I don't know how to use 
yet -- but I would have thought that the convert-ly process would have 
caught that, or else I'd be getting a compile error...

Thanks for any help!
Kieren.