You can always add a shell alias to the s:Shell-Startup script that will call your editor from its real path using whatever alias you choose.
So, using the VIM: assign mentioned by squidbass for example:
Alias vi vim:vim
Or by using its full path, say it's "Work:Productivity/Vim/vim"
Alias vi "Work:Productivity/vim/vim"
Now, to edit that text file, you would simply type "vi workbench:misc/text.txt" in your shell.