[pdftex] pdf objects with references to each other?

[Robert Howlett]

I find that if I use pdftex to create a pdf file containing a
text annotation then when I subsequently use acrobat 5 to
optimize the pdf file it modifies my text annotation in a way
that I do not want. In fact it includes a "popup" annotation
whose dictionary has an M entry that I don't want.
I can circumvent this by including a popup annotation, but
it is a bit painful. I have to say something like this:

  \pdfannot width 12 cm height 2 cm depth 10 pt
  {/Subtype /Popup
  /T (Algebra 1)
  /Open false
  /C [0 1 1]
  /Contents
  (Lectures given at the University of Sydney for the course
  Math3902.)}
  \pdfannot height 2 cm depth 10 pt
  {/Subtype /Text
  /C [0 1 1]
  /Popup \the\pdflastannot\space 0 R}%

i.e. the T and Contents entries go into the popup
instead of the text annotation itself.
What I would have liked to do is have the T and Contents
entries in the dictionary of the text annotation and
put a Parent key in the dictionary of the popup referring
back to the text annotation. However, this means having
entries in the dictionaries of each text annotation
and the popup annotation referring to the other.
I can't figure out a way to do this with pdftex.
It seems to me that I need to be able to tell pdftex to
choose some number that has not yet been used
for an object, create an indirect reference to a
yet-to-be-constructed object with that number, and then
later make an object with that number.
Can this be done?

Bob Howlett