KM navigation IView Layout

Hi, i have a KM navigation IView, and i want to change the layout.

I set up the following:

1. 'Layout Set' property to 'TreeListPreviewExplorer';

2. 'Layout Set for Root Collection' property to 'TreeListPreviewExplorer';

3. 'Layout Set Mode' to 'as default'.

It doesnt works.

I hope somebody can help me.

Thx and Regards.