No you do not need the Premium Edition.
(You do need to register your Docs to Go to get the Sheets though).
Do what you did before. From what I have read you saved the document ot the Media Card and you browsed the Device Memory.
You will have the same folders on your media card (Documents, music, pics, etc...)
Navigating through the dialogue menu is a little tricky and funky but keep playing with it until you get to a screen that says:
Open FileMedia Card
Device Memory
Click on Media Card > BlackBerry > Documents
David
David