I have seen that.try cost2cost.according to their online rate list they are selling core2duo 2.93GHz for 5990.
check for bios update at motherboard manufacturer's site. at times updated bios enable support for new processor of the same series.
strange that E7200 is the first processor from Wolfdale lineup. so if E7200 is supported, anything upto E7600 too should have been supported as they have same TDP & are made using 45nm node.