psql dates in Access

in postgres 7.2
Using the postgres timestamp with timezone, I can't seem to extract records using Access and requesting a range of dates, unless the date is hard-coded into the Access query.

I want to reference a range of dates that a user has entered on a form.
I have referenced to user-entered dates with and without the date bracketed by "#".
In the date range I submit to the query I have referenced the full time stamp string where I construct the start date as "xx/xx/xx 12:00:00 AM" and the end date as "xx/xx/xx 12:59:59 PM" (not the same xx/xx/xx obvioulsy)
I have referenced the dates with and without the double quotes.
I have referenced only the left 10 characters of the dates, i.e., the day part.

When I manually enter the desired dates into the query before saving, then running, it works.
When I try any of the above ways to reference a date from a form, the query results are always empty.

Any ideas?
Thanks
Fred Parkinson