The way I handle this (It might not be the best solution, it depends on the environment) it to use the page setup in the report designer and save your report with the appriopriate tray seleted. (This solution works for me. I have a 7 page report and the last one has to come out of tray #2 - it's a sticker tray)

Or You could hack the report by code, the information for the printer settings is located in the field EXPR on the firts record. For example here the info contained in one of the reports I have in the Expr field:

DRIVER=WINSPOOL
DEVICE=IBM 4039 LaserPrinter Plus
OUTPUT=LPT1:
ORIENTATION=0
PAPERSIZE=1
COPIES=1
DEFAULTSOURCE=2
PRINTQUALITY=600
DUPLEX=1
YRESOLUTION=600
TTOPTION=4

Before your run your report use this:

use c:\myproject\reports\myreport.frx

replace expr with the appropriate values in this case the DEFAULTSOURCE = 2
refers to tray #2.

If your not sure of the tray #. Use the first solution, open the report as a table and find out what is the tray #.