Can I ask why you need a button, when you can just right-click and refresh? (or use Data-Refresh data)
As you've already noted, you can't use macros or events since they are VBA based. Are all your users on XL2008 too?
Because it's better to design for your target audience!
There's not much point coming up with an Applescript solution if 95% of your users can't use it - you might as well design a VBA solution for them (especially as it will be about 2 lines of code)?