HSO content set for halion sonic in cubase studio 5.5.2

hello ,
i am currently on cubase studio 5.5.2 , i also have halion sonic 1.5 , i was wondering if i could buy the halion symphonic orchestra sound set activation key ( for halion sonic ) , then download the content , and then use that in halion sonic and cubase studio 5.5.2 without upgrading to cubase 6 ?
cheers for your time !!!
is there any word on the release of some additional content sets for halion sonic , third party or steinberg ?