I still miss something in your logic. In comments I thought about different-reverse logic which would go this way. This code below is a mix of my way and code you presented.
Class Module
Public WithEvents App As Word.Application
Public pSSave As Boolean 'your class variable/property
Private Sub App_DocumentBeforeSave(ByVal Doc As Document, SaveAsUI As Boolean, Cancel As Boolean)
If pSSave = False Then
MsgBox pSSave
Else
MsgBox pSSave
End If
End Sub
Module1
'class initialization
Public wrdAPP As New myClass
Sub set_References()
Set wrdAPP.App = Application
End Sub
ThisDocument Module
Private Sub Document_Open()
'to initialize public variable when open
Call Module1.set_References
End Sub
Sub FileSave()
wrdAPP.pSSave = True
Application.ActiveDocument.Save
If wrdAPP.pSSave = True Then
MsgBox "True"
End If
End Sub
I don't know which way you are going to run FileSave
sub. But after it is run it pass the value to class property which you could check in your event.
Hope it would help you anyway.