You don't state this but based on your question I am assuming that you have somehow hidden the standard Saves button.
It is unclear what you mean when you say "the manual save and load", are you talking about:
1. Revealing the standard Saves button again.
2. Showing custom links in the side-bar which make reference to the save & load functions of the Save API.
The conditional part is fairly easy, simple store the 'password' in a story variable and then use an <<if>> macro based on the current value of the variable to determine what should be shown.
<<if $password is "some value">>/* include code to 'show' manual save & load. */<</if>>
... where exactly you place the above code depends on the answer to my previous quesion.
warning: Because you are making a HTML based web-applicaton the end-user has full access to the source code of your story HTML file, this means it is fairly easy for them to determine what the required 'password' is.