a metronome mark question

[Dave Phillips]

Greetings:

 I've written a part in even eight notes, but I want to indicate in the 
metronome marking that the rhythm of the even eighths should be played 
with a swing rhythm, i.e. an eighth-note triplet with a quarter note 
followed by an eighth. In a score the rhythm would be {\times 2/3 {c'4 
c'8}},  and some jazz scores indicate that evenly notated eighths should 
be played with this rhythmic figure.

 The Metronome Marks section of the manual (8.2.2 for LP 2.8.4) shows 
how to do what I want, but only for single notes and not at all for 
triplets.

 If I've made myself clear, does anyone know how to create the mark I 
need ? In pseudo-LP code it's something like this:

    {c'8 c'} = {\times 2/3 {c'4 c'8}}

Best regards,

dp