Display Dialog with Hidden Answer

Question

Now Im trying to use a hidden answer dialog to get a password and pass it to the next step in my Automator Application. The code I have so far is:
on run {input, parameters}
          set theScript to input
          tell me to activate
          display dialog "What is your password?" default answer "" with hidden answer
          set ACP to text returned of result
          set keychaincan to input & ACP
          return keychaincan as string
end run
I know this works without the hidden answer, and I cannot see why its failing with "with hidden answer" at the end.
I get the automator error "Syntax Error. Expected end of line, etc. But found identifier."
Any ideas?

Answer 1

Automator has its own variation of several things such as display dialog - you can see the terminology provided by looking at Automator's scripting dictionary.  The Automator version of display dialog doesn't have a hidden answer parameter, so one workaround is to use something like System Events, which will wind up using the regular StandardAdditions version:
    tell application "System Events" to display dialog "What is your password?" default answer "" with hidden answer