Preprocessing with Caret package

Hi,

Please consider the following code

library (caret)
x=matrix(c(12:131),2)
p=preProcess(x, method=c("center","scale"));
x.prep=predict(p,x)

y.prep=x.prep[60,60]

How can I get the value of y (the value from y.pre not centered and not
scaled ) using p and y.prep?

Thank you!
Rui