No problem about old topic! The properties you mention are tile properties, not tileset properties. The "Object Alignment" is a tileset property, which affects all the tiles in that tileset. You can open the tileset properties by opening the tileset and then through the menu Tileset > Tileset Properties. I recommend just using the latest snapshot version (Tiled 1.3.4 does not have this property yet).
Viewing post in Tinting, Alignment and Object References comments
Thanks for your quick reply!
OK, I found it. I thought it was a "tile"-property because each of my objects on the layer has a different "anchor"-point and I wanted to specify that point for each tile.
The option does not allow individual pixel values, but thats fine. With the "bottom" setting I can place the objects and when loading the map in the game I can calculate the "correct" position.
Thanks again and keep up the great work!