R help - Jun 2008 - setvalue of a combobox

if I wanted to set the value of a combobox 

tt <- tktoplevel()
box <- tkwidget(tt,"ComboBox",values=c(1,2,3))
tkgrid(box)
tcl(box,"setvalue","first")

does anybody know how I would access an index other than the first? as second,
and numbers do not work..

thanks in advance

Andreas Posch