How to override the advanceddatagridcolumn ??

Hi, all

I have to override the advanceddatagridcolumn for new properties and functions. When i override the column ,  it can not be display when dragging into flex builder , but it can display when running.

so , which methods should i override then it can be display when dragging into flex builder ?

Is there anybody have the experences in this ?  Help me , very very 3Q.