Excel 2007 : Alphabetize 4 letters in a single cell formula

I want to alphabetize a single cell sting like "HARD" to "ADHR" using a single cell formula. No VBA allowed.

I could do it if
Small({Code("H"),Code("A"),Code("R"),Code("D")},1)
would do what I wanted.

Any suggestions?

See attached for Alphabetizing 3 letter strings works and how I get stuck.