Vim: Map ctrl+pgup and ctrl+pgdn (CTRL+Page Up/Down) key combinations

I'm trying to map Vim commands to the ctrl+pgup and ctrl+pgdn key combinations. The vim syntax for these keys does not work (i.e., <PageUp> and <PageDown>, or <C-PageUp> and <C-PageDown>).

Since the default vim syntax doesn't work, I'm guessing that the Terminal isn't sending the character codes for ctrl+pgup and ctrl+pgdn which Vim is expecting. If that's true, I'm not sure how to find out what the literal key codes are. I'm using xfce4-terminal on Arch Linux.

Here's what I've tried:

1. The usual method:

   map <C-PageUp> :bp<cr>
   

2. Setting it from the command line with this answer's method: Why <C-PageUp> and <C-PageDown> not work in vim?

   :map <CTRL-V><CTRL-PAGEUP> :bp<cr>
   

   When I type the command above in the command line, nothing shows:

   map  :bp<cr>
   

   And Vim says No mapping found.

3. This method from the Vim wiki: http://vim.wikia.com/wiki/Mapping_keys_in_Vim_-Tutorial(Part_2)#Key_notation

   set <PageUp>=<type Ctrl-V><type PageUp> "^[[5~
   map <C-PageUp> :bp<cr>
   

4. A modification of that answer:

   set <C-PageUp>=<type Ctrl-V><type Ctrl+PageUp> "^M
   map <C-PageUp> :bp<cr>
   

5. After realizing that <type *> was a user command, I did these commands, and vim pasted output. I replaced <type *> with this output:

   set <PageUp>=^[[5~
   map <C-PageUp> :bp<cr>
   " Also:
   set <PageUp>=[[5~
   map <C-PageUp> :bp<cr>
   " Also:
   set <PageUp>=<^[[5~>
   map <C-PageUp> :bp<cr>
   " Also:
   set <PageUp>=<[[5~>
   map <C-PageUp> :bp<cr>
   " Also:
   set <C-PageUp>=^M
   map <C-PageUp> :bp<cr>
   " Also:
   set <C-PageUp>=<^M>
   map <C-PageUp> :bp<cr>
   

6. Trying all of the methods in 5, but without setting an option first. E.g.:

   map <C-[[5~> :bp<cr>
   

7. The method from this answer: https://groups.google.com/forum/#!topic/vim_use/j85-2xQkb7s

   map [5~ :bp<cr>
   

8. The method from this answer: https://superuser.com/questions/322983/how-to-let-ctrl-page-down-switch-tabs-inside-vim-in-terminal-app

    map \033[5;5~ :bp<cr>
   

9. Setting different term options:

    set term=xterm
    " Also:
    set term=xterm-256color
   

   My $TERM environment variable is set to xterm.

10. Using some of the methods which this answer hints at: https://superuser.com/questions/480215/how-to-map-pagedown-and-pageup-keys-to-function-normally

     map <Esc>[5~ :bp<cr>
     map <kpp> :bp<cr>
    

11. Trying everything above with a file under .vim/after/plugin/ instead of in .vimrc.
12. Trying everything above with :MBEbp instead of :bp.

What else can I try?