Ok, well here it is. When I said there was a 01 placed in memory just for collecting any sns item, I mislooked at the data. It looks like the flags that are placed into memory are not put there as 01, but as 0X01. The ice-key is 0601, when you collect it, the bk pack writes it to memory as so:
http://i177.photobucket.com/albums/w...icekeyself.jpg
Also, once you collect the blue egg, it is stored in memory as 0301 like so:
http://s177.photobucket.com/albums/w...eeggicekey.jpg
Plus, notice how it switches spots with the ice-key.
The first digit 03 seems to be the item number, this is how the other games recognize wich item you have collected, 01 must mean that this item has been collected.