Customizing xrefstyle globally

I've just finished carefully reading the chapter in Stayton's
book on `Cross-references,' but there's one thing I can't figure
out how to do.

When in my FO customization layer I set insert.xref.page.number
to 1, I get the default style of page number cross-references,
namely, the page number in square brackets, e.g., "[12]".

What I'd prefer is that such page numbers occur in the
xrefstyle="select: title pageabbrev" style, e.g., "(p. 12)".

Since I'm using the 1.65.1 stylesheets but the DTD is only
DocBook 4.2, I could achieve this by adding this attribute to
every <xref> element:

    <xref role='select: title pageabbrev'/>

However, I'd prefer to have this style of page number reference
be the default in my customization layer, so I don't have to add
this attribute in a zillion places.

I spent some time grepping around the stylesheets, but I couldn't
figure out where the templates connect with the gentext templates
for "pageabbrev".

Any suggestions?

Best regards,
John Shipman (), Applications Specialist, NM Tech Computer Center,
Speare 128, Socorro, NM 87801, (505) 835-5950, http://www.nmt.edu/~john
  ``Let's go outside and commiserate with nature.''  --Dave Farber