As far as I am aware you need to cut the strap, add the clips and sew back together.DO I??
Hell no!
Is that the best way forward then to cut them and then sew the old clips back in?
what does the end of you new strap look like? is it a T shape? thats how my KM strap came.
if so, you just need to cut the old strap off and push the new 1 through. If not , go with what DC said.