[Rd] override pmin/pmax for my own matrix

[Da Zheng]

Hello,

I'm trying to override pmin and pmax for my own matrix. These two
functions have ... as an argument. I tried to override them as
follows:
    setMethod("pmax", class_name, function(x, ..., na.rm) { ... })

I use this way to override primitive functions such as min/max and it
works fine.
But it doesn't work for pmin and pmax. I guess because they are
regular functions?
How do I override a regular function with ... as an argument?

Thanks,
Da