I'm using a 940 UW in my 7300 now and it works fine with 2 U2W LVD drives. But it would not take the latest firmware. I'm using version 3.22 It boots fines but there is a bus conflict with the internal cdrom so I have to use the external for my kids games. I'm actually taking it back because of this and for $50 more I can get the Initio Miles U2 card which will give me the Max speed from drives.
And yeah from some posts on MacFixit.com tech support is not stellar, although I did get half an answer from someone at Orange. You can get one and download all the recent firmware updaters then work your way up until it won't boot or something else happens. Or try the Adaptec 2930 I hear that is a good card. And Adaptec has better support as well. Or you could try one of the Initio cards.
Good Luck