HI jskfan,
Actually you didn't forget - I missed it! Sorry about that.
Have you granted yourself the permissions to be able to manage the DNS server in Domain 2? In domain 2 you can add your account to the 'DNSAdmins' group in the 'Users' container. (in fact it is better practice to create a global group in your domain, add yourself to that, then add the global to DNSAdmins).
This will enable you to add the DNS server from domain2 into your mmc whilst you are logged on in domain1.
Hope this helps...