Separator Pages for Printers

Separator pages work just fine in Windows except when printing to HP Laserjet 5SI’s. I configured the .sep file to say what I want and it works good on every printer but a 5SI. The 5SI prints the page OK but it prints it on 11×17. It’s not in the .sep file because all other printers print the page on 8 1/2 x 11.

I have looked into the settings on the printer itself but do not see any options to change the default tray for a separator page. Users need to print 11×17 so that tray must stay there but something must be telling the 5si to print that separator page 11×17.

The answer I am looking for is how to get it to print on 8 1/2 x 11 or a free third-party product that prints banner pages to try them instead.