Link class inhereting from ListFieldIterator to a document list programatically

Hello All

I need to control the display of certain fields in a list according to the current user.

I implemented it using a class inherited from ListFieldIterator .

now , I want to connect the class i created to the document list, and I need to do it programatically

I created a usercontrol and copied its markup from DefaultTemplates.ascx usercontrols in CONTROLTEMPLATES

but still when I try to debug it does not catach the code.

How can it be done?

Shlomy