Merge Replicate and Mirrors

Question

I am preparing some scripts to setup merge replication in our production environment. After completing the export from UAT, I've come across something that doesn't appear like it would work in the production environment?

exec sp_addmergesubscription
    @publication = N'<snip/>',
    @subscriber = N'<Server Name>',
    @subscriber_db = N'<snip/>',
    @subscription_type = N'pull',
    @subscriber_type = N'local',
    @subscription_priority = 0,
    @sync_type = N'Automatic'

The problem I have with this is that the subscriber name is hardcoded to the physical server name of the subscriber DB. In UAT that's fine because the subscriber is a single server, in production that's a problem because there are three production subscribers with mirror partners.

What name should I be using for the subscriber? If I leave it as NULL as the documentation indicates I can, what are the implications of that?