Change IP for seondary nameserver?

[xLnT]

Hi!
I have a server running latest Plesk.
I have multiple exteral ip-addresses and bind (dns) is using 2 of them.
ns1.domain.tld is 1.2.3.4
ns2.domain.tld is 1.2.3.5

How do i make bind to only listen on one ip (the ns1).
I have installed and setup a secondary slave server on an external server. And i whant to use that as ns2.

But i can't find a way to make plesk only listen on one ip-address. Any ideas?

Kind Regards
/M