How can I get bash to perform case insensitive tab-completion for my aliases and functions?

Question

I have an alias like this:

alias sshUntrusted='ssh -X -C -c blowfish-cbc,arcfour'

But when I type

$ sshun

followed by Tab, Bash does not complete the alias.

I have put

set completion-ignore-case on   #ignore case while completing

in my .bashrc, and it makes Bash perform case insensitive tab-completion for filenames.

How can I make it complete aliases and functions in a case insensitive manner?