Were did you find the info with the date change, I have tried all kinds of crazy procedures that I have read on the net...did this solve getting regular updates on the store tile or do you have to do this on occasion to get updates? I know the 8.1 update will address this problem.
I searched the WPCentral Forum. There is a wealth of information here. I don't use the Store live tile but I do check the Store periodically and update notifications are displayed upon opening the app. Ah, WP8.1, won't be long.