getting panel.loess to use updated version of loess.smooth

I'm updating the loess routines to allow for, among other things, 
arbitrary local polynomial degree and number of predictors. For now, 
I've given the updated package its own namespace. The trouble is, 
panel.loess still calls the original code in package:stats instead of 
the new loess package, regardless of whether package:loess or 
package:lattice comes first in the search list. If I export panel.loess 
from the new package, then it can't see grid.lines anymore.

I've tried using fixInNamespace to change the loess.smooth in 
package:stats to point to the updated simpleLoess, but it is locked. At 
http://tolstoy.newcastle.edu.au/R/help/04/05/0428.html it was suggested 
to write a new panel function. However I still need to be able to access 
grid.lines, and getFromNamespace("grid.lines","grid") is not the way to 
do this.

Any ideas? This seems simple but I'm stumped.

Thanks,
Ben

Can you show us what you tried? It seems as simple as defining a new 
panel function:

panel.loess2 <- function (x, y, span = 2/3, degree = 1,
                           family = c("symmetric", "gaussian"),
                           evaluation = 50, lwd = add.line$lwd,
                           lty = add.line$lty, col,
                           col.line = add.line$col, ...) {
   x <- as.numeric(x)
   y <- as.numeric(y)
   if (length(x) > 0) {
       if (!missing(col)) {
           if (missing(col.line))
               col.line <- col
       }
       add.line <- trellis.par.get("add.line")
       #smooth <- loess.smooth(x, y, span = span, family = family,
       #                       degree = degree, evaluation = evaluation)
       smooth <- simpleLoess(x, y, span = span, family = family,
                             degree = degree, evaluation = evaluation)
       grid.lines(x = smooth$x, y = smooth$y, default.units = "native",
                  gp = gpar(col = col.line, lty = lty, lwd = lwd))
   }
}


--sundar