xyplot() method for profile objects: error from use of the scales argument

I take it that I should be able to supply a ?scales' argument in these circumstances:

fm01ML <- lmer(Yield ~ 1|Batch, Dyestuff, REML = FALSE)
tpr  <- profile(fm01ML, optimizer="Nelder_Mead", which="beta_")
xyplot(tpr, scales=list(tck=0.4))

Error in xyplot.formula(scales = list(tck = 0.4), x = zeta ~ pval | pnm,  : 
  formal argument "scales" matched by multiple actual arguments

These are, incidentally, elegant plots.

John Maindonald             email: john.maindonald at anu.edu.au
phone : +61 2 (6125)3473    fax  : +61 2(6125)5549
Centre for Mathematics & Its Applications, Room 1194,
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Australian National University, Canberra ACT 0200.