Commit to trunk from branch

[Lemke, Michael IZ/HZA-IOP]

Suppose I am on a branch.  I add a file.  How do I commit it to the trunk?
Instead of the branch.

cvs ci -H says
Usage: cvs commit [-Rlf] [-m msg | -F logfile] [-r rev] files...
    -R          Process directories recursively.
    -l          Local directory only (not recursive).
    -f          Force the file to be committed; disables recursion.
    -F logfile  Read the log message from file.
    -m msg      Log message.
    -r rev      Commit to this branch or trunk revision.

so I tried 

  cvs ci -r HEAD my_file

but I get 
RCS file: /inaetc/bfsaparc/cvs/repos/ina/project/inacom/Attic/dblog,v
done
cvs server: Attempt to add reserved tag name HEAD
cvs server: could not stub branch HEAD for 
/inaetc/bfsaparc/cvs/repos/ina/project/inacom/Attic/dblog,v


Why I want to do this?  Don't ask.  We are misusing CVS as a transport tool and
I can't switch the sandbox to the trunk.


Thanks,
Michael