question on how to add plugins

[dre@mer]

Hi all very nice the new forum.
Glad to be a member...
I have a question about adding my own plugins on my new compiled original image.
I have make the compile and now i want to add some plugins that after the rebuild will be allready instaled.
I try to put the ipk on build/tmp/ipk but when i make image again they didnt install and dont see them on plugins selection.
Can someone explain how and where we put the ipk's so that the plugins will be pre installed on new build?

Thank you