I want to sync existing files on my Vision M

[poppycock]

Hi I have recently bought a Creative Vision:M and I have also just discovered Media Monkey, which seems the ideas programme for managing my large music colllection. My problem is that I already transferred my Music library to the Zen (it is broadly in two sub folders 'Artists' and 'Collections') using Zen's own software.

What I want to do is use MM to keep the Zen up to date with changes to my Music library on my PC. I tried to Sync with MM specifying the correct path on my PC. Without warning MM said 'deleting exisiting data' (or something like that) and started to wipe out files from my ZEN !!!!! I had to cancel thsync and manually repair the damage)

Is there a way I can use MM to compare the two file structures on the Zen and my PC (which are essentially the same) and recognise which files to update?

Or, does it mean I will have to wipe the music off my zen and start again?
Is there an idiots guide to syncing that tells me whats going to happen before MM starts doing things that I don't want it too?

Thanks for any help - If there is a Zen Vision M user out there who has it all sussed out then please tell me your secrets