RoboCopy or XXCopy…whatever, I need syntax!?

Seems simple, but I can’t figure it out…I need a sync program that will overwrite all destination files, copy all new source files to destination (creating directories if needed), but not overwrite newer files in the destination. Specifically, I’m looking for the syntax to make this work with either RoboCopy or XXCopy. Really any program is fine, but I’ve tried UltraEdit’s compare util, SyncBack, Vice Versa, SuperFlexible Sync, GoodSync, WinMerge, etc and can’t find one that will overwrite all but leave newer destination files alone.
If no one here knows, can someone point me to a more proper forum for such an issue?

The source should remain untouched. Thanks for your help!