I had some study about CBA for years and I'm sure my idea is fesiable, there would be a few executive details, but it can work.
As I know, u can always trade one player for "Trade Exception", as long as the other club take it.
Diaw for the #6 pick and Trade Exception, we take no salary in return.
Barbosa for
David Lee and another Trade Exception or fillers, depends on how much salary the Knicks could absorb.
It all depends on how much the Knicks want Diaw and Barbosa, and how Dolan and their new GM think about luxury tax. Please be aware, they have always been a tax paying club, even b4 Isiale's era.