asterisk users - Mar 2008 - How to return the status of a call to the calling server?

I think tilghman hacked out something like this in less time than it took 
me to search through 20 pages of googlegook trying unsuccessfully to find 
it :)

A caller calls host A. They select a service provided by host B which is 
invoked using dial(iax2/service at hostb/${EXTEN}|2|g).

The service on host B needs to return a single digit to host A's dialplan. 
(I really only need 1 bit that I can interpret as "this" or
"that.")

Executing hangup(${EXTEN}) on host B and testing ${HANGUPCAUSE} on host A 
seemed obvious to me. Sad to say, it doesn't to the developers :(

Abusing CALLERID(name) didn't work either.

Writing a row to a MySQL database seems so cumbersome.

This is for 1.2 if it matters.

Thanks in advance,
------------------------------------------------------------------------
Steve Edwards      sedwards at sedwards.com      Voice: +1-760-468-3867 PST
Newline                                             Fax: +1-760-731-3000