afni.nimh.nih.gov

You say "I want to append the tlrc + acpc files of head+orig to brain+orig". Do you mean that you want to use the +orig -> +tlrc transformation you set up in head+orig to transform brain+orig to get brain+tlrc? If so, then a command like
adwarp -apar head+tlrc -dpar brain+orig
should do the job. If this isn't what you want, then can you explain what you want in more detail?

bob cox