asterisk users - Jul 2009 - Struggling with Macros and "s" Extension

Hi all,

I'm sure this has been done before but I just can't figure it out.

On my * box I have a simple IVR:

[tolc_menu] ; Welcome and information to callers
exten => s,1,Answer()
exten => s,n,Wait(2)
exten => s,n,Background(welcome-to-tolc) ; Say Hello
exten => s,n,Wait(1)
exten => s,n(tryagain),Background(enter-ext-of-person&or) ; Enter 
extension number if known, or
exten => s,n,Background(pls-stay-on-line) ; Trying to connect...
exten => s,n,WaitExten(5)
exten => s,n,Macro(belllord,${ALANL}&${ALANB},303)

exten => _10[1-5],1,Macro(call_extension,SIP/${EXTEN})

exten => _20[1-5],1,Macro(call_extension,IAX2/alanb/${EXTEN})

.
.
.

Hopefully you'll see that the caller can either enter an extension 
number or wait. If they wait, we use macro-belllord:

[macro-belllord]
exten => s,1,Dial(${ARG1},20,t)
exten => s,n,Goto(s-${DIALSTATUS},1)

exten => s-NOANSWER,1,Voicemail(${ARG2}@business,u) ; business is the 
voicemail context, ${ARG2} is the mailbox number to dial
exten => s-NOANSWER,n,Hangup()

exten => s-BUSY,1,Voicemail(${ARG2}@business,b)
exten => s-BUSY,n,Hangup()

exten => _s-.,1,Goto(s-NOANSWER,1)

The Vars ALANL and ALANB are:

ALANL=SIP/101
ALANB=IAX2/alanb/202

If I call in, dial the extension (say 101) and connect, then the Link 
Event on the AMI port (and in CDRs) correctly displays *both* numbers of 
the connection.

For that scenario we use macro-call_extention:

[macro-call_extension]
exten => s,1,Dial(${ARG1},20,t) ; Ring channel for up to 20s
exten => s,n,Goto(s-${DIALSTATUS},1) ; Go to either no answer or busy.

exten => s-NOANSWER,1,Voicemail(${MACRO_EXTEN}@garden_house,u)

exten => s-BUSY,1,Voicemail(${MACRO_EXTEN}@garden_house,b)

exten => _s-.,1,Goto(s-NOANSWER,1)


If however I wait and let macro-belllord do it's stuff. I only ever see 
"s" as the called party's number.

I really need to know what that extension number is.

Could someone help me and show how I can rejig this? It was suggested to 
do something with ${MACRO_EXTEN} but I can't get it at all...

Many thanks in advance.

Alan