using "by" and indicies

I sent this to the list last week, and haven't seen it pop up.  Either 
I deleted it when it did appear, or possibly it was destroyed as 
spam...?  If it did appear and I somehow missed it, appologies.

I'm using by() to call pairs(), and would like to put the factor
level into the title.  A toy example would be something like:

d1 <- data.frame(rnorm(100),rt(100,2),sin(1:100))
levs <- as.factor(rep(1:5,20))
levels(levs) <- c("low","med-lo","med","med-hi","high")
by(d1,levs,pairs)

Is there an elegant way to get "low"..."high" in the main title for
each plot, without binding "levs" to the data sent to a custom plot 
function? 

d2 <- cbind(d1, levs)
by(d2,levs,function(x){ tmp <- levels(x[,4])[x[1,4]] ;