So...I have been banging my head off the wall trying to figure out where my "valet switch" may be located...IF...I even have one !
Most systems the valet switch is located in the driver underdash or kick panel. On newer systems most of the manufacturers are incorporating the switch into the antenna which is normally mounted on the windshield. Depending on who installed your system you may or may not have the switch at all. It isn't uncommon for them to not be installed as many systems we program using a programmer versus the switch and also we generally don't want the end user to be messing with the switch. Most systems once you enter programming mode hitting the wrong button can set all options back to default.
Also are you saying your trying to program a remote from a different system/manufacturer? Remotes are very specific to what they will work on and unless the FCC id on the remotes you have now matches the ones your trying to program the chances of it working are slim to none. Anytime you go for a new remote you want to make sure you get one that looks the same and has the same FCC id / part number. Hope it helps,