RGB to CMYK conversion problem (help preserving Cyan color)

Hi,

I love creating designs in colors that turn out not to translate well between RGB and CMYK - and therefore, SwiftPOD (for example) does not print the colors I intended to have.

My colors are just plain white seperated into the Red Channel (Red), and Blue + Green channels (Cyan).

Looks like this:
image

When I change the mode to CMYK, I get these colors:
image

Which is a duller blue instead of a light turquoise cyan.

Questions:

  1. Can I recreate the above Cyan color in CMYK format?

  2. How can I convert from RGB to CMYK while preserving the Cyan color?

Thanks!!!

Do you have specific software in mind?

Also, some colours may be in gamut for one device, but out of gamut for another, meaning they cannot be represented.