We do not currently have metric unit support in our software.  Please refer to the following information for conversion to metric units.

CD Jewel Case size is 4.75" x 4.75" which corresponds to 12.065cm x 12.065cm.

Calendar Case size is  4.75" x 5.5" which corresponds to 12.065cm x 13.97cm.

Paper size of 4"x6" corresponds to 10.16cm x 15.24cm. 

Our margins correspond to approximately the following:

1/8" = .3175cm
1/4" = .635cm
3/8" = .9525cm

We may consider adding better metric support in a future release.

We currently do not support printing to any paper sizes other than 4"x6" or paper that is larger than the desired output size.

An interesting article about metric paper sizes can be found here:

http://www.cl.cam.ac.uk/~mgk25/iso-paper.html