At present it is not possible to dial a single # key from AA; the AA will interpret a single
# as a command to leave the current option.
Suppose you are willing to use, say a single * key to do the same thing, you can
Add a single digit rule in the AA Service digit map, |*|
and add a routing rule in the AA Service OutboundCallRoute, {(<*:>):li}
(Note:make sure you don't have a typo when submitting the changes)
When you hear the AA, select option 2, and dial * #
to get dial tone from your KS.