items menu?

ive got a menu in my game for items. Its a big raster. And i got little item-textures on Planes to symbolise the item my character has got.

Now i want these little item-symbols to snap with my raster-fields in my item-window.
I know there would be the way of setting a LOC in the IPO for every plane to every rasterfield, but that is way to complex and it still doesnt sort my items. Thats the next thing i want to do.
The items should be sorted. Maybe automatically in a row or manually with the mouse.

How do i do the drag and drop thing with the mouse and how do i tell these item-planes to only stay inside of a raster-field and not yust somewhere weired…

That will probably need a python script…but sadly i cant progamm one myself…but maybe someone had the same idea of making a item-menu and has a script or yust another idea…