Acrobat XI pro- Custom plug-ins not shown up on acrobat window

Hi,

              I have installed my custom plug-ins on acrobat XI (with windows 8),  but they don't show up on opening the acrobat window.

              I verified the Edit->Preferences->General->Application Startup and under that, the check box "Use only certified plug-ins is Unchecked and

             Cuttently in certified Mode is No.  Still my plug-ins are not loaded in the acrobat XI window, why they are not loaded? what could be the   

             problem?

             Right now I am using Trail version of acrobat XI.

             Please let me know, how can I make to load my plug-ins on acrobat XI.

thank you,

palaksha