How to convert .ISO file to a .DMG file in Windows?

I recently decrypted a .DMG file in windows. I had to convert it to ISO but now when i need to change it back to a .DMG file i can't seem to find a way! I've seen many ways to do it in MAC OS X! But how do i do this on a Windows Machine? Any programs out there? Thanks! MagicISO and PowerISO won't do it by the way, unless i'm doing something wrong...