while remastering after the kde packages in unstable went from 3.1.3->3.1.4
I had the same issue while removing koffice, it wanted to remove kdebase+
the trick of course is to hold the current version. Had no problem using synaptic for my remaster...
the problem I find it that there isn't an "archive" of the unstable branch so when a new version of kde (for example) comes it has a hard time distinguishes the two versions and craps out. I can't even get ksysguard installed cause it needs the rest of the updates and no copy for 3.1.3-1