This will be tricky. And I hate to say it, but you'll have to use DISA with a security code.
The outbound route will have to dial the DISA, pause, dial and account code, then ARS code + number.
Could work. Don't think I'd trust it. It will add a big delay to the outbound call set up. (as in dial number... wait.... wait.... wait... ring)
And you MAY hear some of the DTMF signaling tones.
Could be fun to play with.
Ralph