FeatureMgr in VB.NET

I connect the application using the following code.

        Dim m_App As MicroStationDGN.ApplicationObjectConnector = GetObject(, "MicroStationDGN.ApplicationObjectConnector") '
        Dim msDGNApp As MicroStationDGN.Application = m_App.Application
        Dim m_DF As MicroStationDGN.DesignFile = msDGNApp.ActiveDesignFile

This is how I get the DesignFile.

From here how will I get the FeatureMgr Class initialized.

Or Is there any othere method. Please help

Liju Mathew Varghese