Yes, you can use eCart 6 to edit a cart created with eCart 5.
and you can use DW CC to edit sites created with DW CS5.5
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.