can't "allow peer to peer" - SQL Server 2005

I'm trying to set up the first distribution server for a peer to peer transactional replication (updateable subscription) between two SQL Server 2005 instances on one machine (for testing). Can this be done without "virtual servers", and if so how do I enable the "Allow peer-to-peer subscriptions" option in the Subscription Options folder of the Publication Properties dialog box?

I've got:

Independent Distribution Agent True (not selectable)

Allow anonymous subscriptions False

Attachable subscription database False

Allow pull subscriptions False

Allow initialization from backup files True

Allow non-SQL Server Subscribers False

Allow data transformations False (not selectable)

Replicate schema changes True

Allow peer-to-peer subscriptions False (not selectable)

Allow immediate updating subscriptions True (not selectable)

Allow queued updating subscriptions True (not selectable)

Report conflicts centrally True

Conflict resolution policy Keep the Publisher

I've tried various combinations of options, but think these are correct. Also, the snapshot database is in a local (not network) directory; I got a warning on this, although in this special case the snapshot should be available to both instances.

Thanks...

I applied SQL Server 2005 SP1 and the problem went away!

Liston