There is actually a NO CD patch on the Ubi website somewhere. Just run a search for NO CD on the forums and you will find heaps of references to it.
The problem is with no CD cracks is that PF sales were really hit hard when the gold master was illegally copied and distributed by several warez groups.
NO CD questions have been something of a sore point with the moderators there and there have been several squadrons boasting about it on HYperlobby.