[ale] cvs tag a date on branch

[leeslist at gmail.com (lyric hartley)]

I am trying to place a tag at a time in history on a branch. I have
tried the following:
cvs rtag -r branchname -D datetotag module (says they are mutally exclusive)
cvs rtag -r branchname:datetotag module (says no such tag)
I have been googleing and it seems other folks have similar issues and
that this is a problem with cvs.
any suggestions?
thanks