[Bugsy]

A key is unique in a vault, so you cannot save multiple items under the same key..the last nvault_set() will overwrite all the previous ones. This is the whole idea behind nvault array, allowing you to save multiple pieces of data under a single key.

Looking at your code it seems as if your mindset is that the variable name has a bearing on the type of data you are saving and retrieving, and this is not the case.

The only thing the nvault module sees is:

nvault_get( vault id , string variable , string variable , length )
nvault_set( vault id , string variable , string variable )