Dovetails at odd angles

[Candy George]

Can anyone direct me to some instructions on cutting dovetails on joints that meet at odd angles - specifically at about a 120 degree angle. I am building a casket, traditional pine box that is wide at the shoulders and tapers toward the feet - for my dad at his request.

Any other suggestions about how to proceed with this project would be welcome.

[Jeff Craven]

Like this?
Tage Frid Teaches Woodworking: Hand Dovetails with Compound Miter. (http://books.google.com/books?id=rCiImAM0Z-cC&pg=PA78&source=gbs_toc_r&cad=0_0&sig=IMT6wL5CpIy4yE8r4iBSQn5MPFE)