Assigning the string with the single &s (i.e. the one that looks like the desired end result) to a text box works just fine.
Me!Text0 = "AADMNN&QUAL..PS060D09.PP&PP.&CY.BU" produces exactly what you entered.
A label is something else... what you are running into seems to be an Access 2003 bug. It works as advertised on 2000 and 97.
You could use a locked text box as a workaround... even saves the hassle of escaping all the ampersands.