Ok, when you go to install you choose the package, then click on Apply Changes
(Green ->) Button, then you get a new window, where you choosed ram as destination and saw the output (it you didnt used ipkg in console to install) there is an options button near the start button. Click on this options button and choose --force-overwrite
If you use ipkg, then just take --force-overwrite as option.
Have fun,
Sam