Using the new 3tb Western Digital drives in a 2 gen drobo

I am confused as to whether I can use a WD 3tb drive in my drobo. MY setup is as follows: intel 27 inch imac running snow leopard, i tunes 10, 2nd gen drobo with the latest firmware installed. I have my itunes library on the drobo and I stream all of my music and movies to my apple tv attached to my hdtv, all of the computers in the house can access itunes using homesharing and everything works great.

I have 3 bays of the drobo filled with WD 2tb drives and would like to add a forth drive. Given my configuration can I safely add a 3tb drive to the empty bay. I know that OS X will recognize the 3tb drive but it work in the drobo and will the full 3tb capacity show up on the drobo. Drobo's website is not clear and it says that they are coming out with a firmware update in the future. Will this firmware update be needed for all computers using a drobo or just those that have operating systems that will not recognize drives larger that 2tb?

Running out of space and would like to get the largest drive I can.

Any advice would be welcome. Thanks.