The Official Samba-3 HOWTO and Reference Guide (Second Edition), has a small mistake at paragraph 18.4.2 (Samba as the Trusting Domain). The phrase "Now, next to the Trusted Domains box..." should read "Now, next to the Trusting Domains box". svn head patch attached.
Created attachment 1890 [details] Diff with the interdomain correction svn samba-docs HEAD patch
Thank you. Patch applied and will first appear in 3.2.0 series releases.