Another options...I saw some examples of dsquery that used *'s as wildcards. Maybe just a quick Split/Join on a few characters is all you need.

 Code:
Break On
$Username = "fbosse"
$UserAccountOU = GetUserOU($UserName+"@@emcobp.com") 
? $UserAccountOU
$UserOU = Split($UserAccountOU,"LDAP://")[1]   ; remove "LDAP://" from string	

If InStr($UserOU,Chr(233))
   $UserOU = Join(Split($UserOU,Chr(233)),"*")   ; if é is in string, it is replaced with a *
Endif
? $UserOU

$CmdLine = 'dsquery user -name ' + chr(34) + $UserName + chr(34) + ' ' + chr(34) + $UserOU + chr(34) + ' '
? $CmdLine
Quit