Easy.  You just need a helper to turn the radio on/off when installing the
new one so that the retraction mechanism properly loads the antenna.  The
only trick is if the old antenna cord broke off in the retraction mechanism.
I think in that case you'll need to remove the trunk liner so that you can
remove the mechanism and get the broken piece out first.

If you run through the archive here
(http://groups.google.com/advanced_group_search) you should be able to find
the details of the procedure.

Dave