Well it's certain that you shouldn't have SystrayX -1 og -0 since the coordinates represent the top-left corner position. If you have a static systray it's easy to define what the SystrayX shold be (simply -(SystrayWidth)) but with autoresize it's kinda tricky because the upperleft corner changes position while the systray is growing or shrinking. I guess -64 is somekind of "magic" number. It also worked for me in the y-direction.
Look at me. I've written a long thread without answering your question.