Prevent an application from being updated

Hi all,
I've got Snow Leopard and a Lexmark X6570 wireless printer. The fact is that from time to time I am getting the darned "Color table is missing" message, which has been described in this forum before. The solution, as posted before, consists in reinstalling the software. I've done this like a dozen times in the past year.
I've found out this is because, even though the original software for Leopard that Lexmark provided works fine, after being installed, Apple Software Update updates it with the latest software apple has for my printer, which unfortunately does NOT work at all. If when having an update available I am very careful, I select what to install and I leave out the printers update, then no problem, but if I unadvertedly click on the OK, the lexmark software gets updated and there we go again.
So now comes the question: is there any way of automatically preventing Software update from trying to install a given software ? In the Windows world, if there is a certain package you do not want to install, you can simply go to Windows Update, unselect it and tell Windows to forget about trying to install it again, at least until you don't tell it otherwise.
Thanks in advance all for your help.