Store your points of interest with 3D view > Store point of view in Sweet Home 3D, then add the viewpoints you want to [font=courier new]selectableCameras[/font] parameter in the generated HTML file (you'll have to uncomment this parameter) (read also Sweet Home 3D JS Viewer README.TXT file).
But the drop down list which lets you choose a point of view will be displayed in the browser only if your exported home contains some levels (they may be empty). This is a bug that I'll try to fix in the next version. If you don't need levels, the trick can consist of adding a level to your home then immediately delete it (don't use Edit > Undo but delete the level).