Look in your webassist/html_editor/xxxxxxx.js file (the xxxxx depends on your page/instance) at about line 20
change:
FCKConfig.EnterMode = 'p';
to:
FCKConfig.EnterMode = 'br';
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.