sounds like a two stage dialing.
First stage - authentication
second stage - collect the digits and place the call
cisco have some scripts which are doing this:
app_clid_authen_col_npw_cli.2.0.0.tcl
# Mimic the clid_authen_collect script in the SP1.0 release.
#
# It authenticates using (ani, dnis) for (account, password). If
# that fails, it collects account and pin number, then authenticates
# using (account, pin).
#
# If authentication passes, it collects the destination number and
# places the call.
or app_clid_authen_collect_cli.2.0.0.tcl
the voice prompts can be loaded from a local tftp server.
cheers