4 bar repeat

[Tim Sawyer]

Hi,

I'd like to produce a four bar percent repeat, is this possible in 2.10?

I've tried this but it doesn't work, but instead gives me four blank bars.  
There are four bars of 4/4 notes between the inner curly braces.

up = \drummode { \repeat "percent" 2 {sn4 sn4 sn4 sn4 sn8 sn8 sn8 sn8 sn4 sn4 
sn4 sn8 sn8 sn4 sn8 sn8 sn8 sn8 r8 sn8 sn4 sn4} \bar "|." }

If I shorten the music down to two bars worth, then I get a correct two bar % 
repeat.

Cheers,

Tim.