@Butrflynet,
This is a good idea - and a kindness ultimately to your fiance. I know it's old fashioned, but I think if you love your guy - you look for opportunities to make his life easier - rather than more difficult. Use your head and make the situation work to your advantage, if you can. Beth suggested a Vow Renewal Service for her - this suggestion of Butrflynet's is good... Also, putting yourself in MIL's place may help you approach her from a less angry position as you work through this. Never giver her her way in your wedding - but beyond that - there are a multitude of routes you can take toward a good resolution. I knocked myself out to get along with Satan in a Skirt before I told her to drop dead and stopped taking her calls...