I had the same struggle and ended up ordering the full set with blue stitching from iND...
I initially purchased the alcantara boot with white stitching for 2ers and thought about replacing the knob with stock but did not work well.
I sold it boot+knob with white stitching to another forumer and he said that he has done the swap, said that he said to drill some holes to remove the knob from the boot.
Read the post that I made asking same question and some forumers that posted reply to here do have experience and u may wanna ask them for detail.
http://f87.bimmerpost.com/forums/sho...ght=shift+knob
Hope it helps