Create a property node from your tab control. From this, select the Pages property. This will output an array which contains references to all of your pages. To access a specific page, index this array accordingly. Note, this must be done using the index array function, "auto-indexing" as an input to a for-loop (for example) does not work for some reason. Once you have indexed the array, create another property node and select PageLabel and set this to writeable. Hope this helps!