Question about screen, vim and function keys

[Zoltan Toth]

Hello,

I have some function keys mapped to some commands for vim.  For example, my 
.vimrc file contains the lines shown below.  This seems to work just fine 
EXCEPT when I am using screen.  Note that I type screen by itself to get 
multiple shells in one window, as oppose to doing "screen vim".  Any idea 
why I'm getting this behaviour and how I can change it?

Thanks for reading this,
Zoltan

" 
-----------------------------------------------------------------------------
"  Toggle various options on and off and show the current value
"   - <F9>  = Paste mode
"   - <F10> = Line numbers
"   - <F11> = Highlight tabs and trailing blanks
"   - <F12> = Word wrapping
" 
-----------------------------------------------------------------------------
map <F9>  :set invpaste  paste?<CR>
map <F10> :set invnumber number?<CR>
map <F11> :set invlist   list?<CR>
map <F12> :set invwrap   wrap?<CR>