two mapscript questions

[Jameson Tweedie]

hi, i have two quick (and presumably incredibly simple, pardon my
stupidity) questions:

1. can you remove a layer from a mapObj using mapscript?
2. can you change a layers position within a mapObj using mapscript?

i've checked through all the mapscript documentation i can get my hands
on and haven't seen an solution.  it would seem logical that they both
exist and to me the most logical option for the changing layers would be
to simply be able to change a layers index value, but that seems to be
read only. how do i go about doing these?
thanks jameson.