Will the E5700 work with a 680i LT SLI mobo?

I bought an E5700 to upgrade an older machine with a 680i LT SLI motherboard by XFX. All of my searching told me it should work with any Core 2 or Dual-core Intel processors... that is until AFTER I ordered it and it's "out for delivery".

NOW I find that in order to get XFX support data you have to actually register with their site and jump through a few hoops. I found my mobo on their site, pulled up a "processor compatibility list" and, to my horror, E5700 is not listed.

Does that mean it's definitely not supported, or is it just not listed on that particular page (perhaps because it's not been updated recently)?

Would it do any harm just to try it out, or should I go ahead and get the dreaded RMA?