fdtd cylindrical

I am asked to calculate the EM field with FDTD in cylindrical coordinate, and not permit to use conformal FDTD, just use cylindrical FDTD.
I do not know how to deal with it, especially the PML(absorbed boundary condition) in cylindrical coordinate.
Would anyone like to give me some advice or paper(reference materials)?
thank you.

Here are 3 excellent references about PML:

1) Original concept (introduced by Berenger):

Perfectly Matched Layer for the Absorption of Electromagnetic Waves

2) An improvement (also by Berenger):

Improved PML for the FDTD solution of wave-structure interaction problems

3) another good paper (By Sacks et al.)

Perfectly matched anisotropic absorber for use as an absorbing boundary condition

Enjoy!
mogwai.