I need to quilt on butter cream, any suggestions on how to do this?

I've used an impression mat on buttercream and it worked great. I order it from sugaredproductions.com.

I used an impression mat as well.
This is my most recent quilted buttercream.

http://www.keeponcaking.com/2011/03/christening-cake/

I like the mat because it works on both fondant and BC and it's pretty easy to use. Just remember there will always be a back because things won't line up dead on.

Thanks I will give that a try.. Wish me luck.

I just ordered mine from sugared productions and used the 10% off discount code. It comes with 4 mats-2 square, 2 diamond (large and small). It came to $14.12 with UPS ground (I am in Texas so there is no tax on it).

I am looking forward to using it on my buttercream wedding cakes that are coming up!

I did this a few weeks ago, I didn't use an impression mat but used a plastic impression cutter (almost like a cookie cutter)? I hope that makes sense. It worked very well.