Solved. I just needed to read the Adobe pdfmark documentation and type a little more accurately.
http://partners.adobe.com/public/developer/en/acrobat/sdk/pdf/pdf_creation_apis_and_specs/pdfmarkReference.pdf
Here's a toy:
%!PS-Aobe-3.0
%%
% If pdfmark is defined, use it (for hyperlinks & other pdf-not-postscript features)
% otherwise give pdfmark a null definition so that we don't get any errors.
/pdfmark where {pop} {userdict /pdfmark /cleartomark load put} ifelse
%
%%
%%
% Document metadata
[ /Author (A clutch of disembodied fingers)
/Title (Aspects)
/DOCINFO pdfmark
%
%%
%%
% A real drawing - an HSBC mark
newpath
100 100 moveto
100 100 rlineto
-100 0 rlineto
100 -100 rlineto
closepath fill
%
%%
%%
% A real hyperlink
[ /Rect [100 100 200 200]
/Border [16 16 1]
/Color [0 0 1]
/Action << /Subtype /URI /URI (
http://www.google.com) >>
/Subtype /Link
/ANN pdfmark
showpage
%
%%
%%
% A link to another point in this document
% First an icon
newpath
300 600 50 0 360 arc
fill
% then a link
[ /Rect [250 550 350 650]
/Border [16 16 1]
/Page 1
/View [/XYZ 50 250 null]
/Subtype /Link
/ANN pdfmark
showpage
%
%%