Item type does not appear on the element automatically

Hi,

I edited the file BRIDGE_FEATURES_LEVELS_ELEM TEMP METRIC.DGNLIB and added an item type on one of the feature definition i created.

When i created a bridge model and modeled a deck, the said item type does not appear on the properties of the element. 

but If i use the command "Attach item type" and attach the item type manually, it works fine. Any reasons why it doesn't work automatically?