Question : Exchange 2007 split DNS concern

i'm setting up Exchange 2007 with a isa 2006 or tmg 2010.  The option of using split DNS for OWA and autodiscovery is becoming more appealing, but I'm concerned about queries that go to that new zone from internal requesters when they request records that aren't added to the new zone.  What happens if someone requests a web site from the new zone that doesn't have an entry?  Will the request fail and the requester won't get to the site, or will it get forwarded to the exterenal zone?  Must I have a complete up to date copy of the external zone records available if i setup split DNS?

Answer : Exchange 2007 split DNS concern

Check this one from sembee (exchange mvp)
http://www.amset.info/netadmin/split-dns.asp