[exim] Cannot find authenticator driver "spa"

Hi,

It's about 18 months since I needed to post to the list, but this one has me
beaten.

I'm using Exim 4.71 on OpenSuse 11.3.
I'm trying to allow connection from somebody using Outlook 2003 (his choice,
not mine) via the SPA / NTLM authenticator.

Having looked this up, I added this to exim.conf authenticators section


SPA:
driver = spa
public_name = NTLM
server_password =
${lookup{$auth1}lsearch{/etc/exim/clientpasswd}{$value}fail}


and restarted Exim only to get the panic message

2011-02-10 13:02:39 Exim configuration error in line 928 of
/etc/exim/exim.conf: authenticator SPA: cannot find authenticator driver
"spa"

I thought the SPA authenticator was built into Exim; I can certainly find no
reference to this error in the list archives.

Am I missing something?

Thanks.

Bill Hayles