The "Replace Design" opton is considered an 'advanced menu option'. By default on All Client installs, the Advanced Menus are enabled, hower,on Notes-only install, they are not.
Take a look at the following technote and try ini if assists you on your task.
Title: Several advanced menu choices in Notes 8 are not displayed by default
Doc #: 1268395
URL: http://www.ibm.com/support/docview.wss?uid=swg21268395