asterisk users - Mar 2006 - ISDN NT Mode & CAPI

I'm setting up an asterisk server to allow our PBX to make calls out via
VoIP, but when it calls out I get this message:

chan_capi.c: did not find device for msn 
(eg no msn)

Which would be correct because at that point I've only asked for an
outside line.

I'm using CAPI obviously, and my config is:
[ISDN1]
ntmode=yes
isdnmode=did
incomingmsn=*
immediate=yes
controller=1
group=1
softdtmf=on
relaxdtmf=on
accountcodecontext=default
devices=2

Any pointers?

Thanks

James