[Asterisk-Users] SIP extension

[Mike Heininger]

Hi,

my VoIP provider routes my main phone number and all extensions to the  
same sip account.
In the sip header of the invite message is the To: field that shows me  
which extension the caller dialed ...

for extension 0:
INVITE sip:2 at ip_of_sipserver SIP/2.0
[...]
To: sip:00431234567890 at ip_of_sip_provider

for extension 10:
To: sip:004312345678910 at ip_of_sip_provider

How can I use this extension information in my dialplan?
I have tried ${RDNIS}  
(http://lists.digium.com/pipermail/asterisk-users/2004-March/ 
041264.html) but this doesn´t work (RDNIS is empty).

I use CVS-HEAD-05/22/04


TIA,
Mike