There´s a post dedicated to answer those questions, but, well here we go:
XWindowsDock supports drag & drop, it means that you locate photoshop.exe icon on your windows explorer and just drag it to the dock, that´s the easy way, the other one is right clickin the dock, then add and then file, a window will popup and sear the file there.
To change it to a custom icon, once you have the shortcut on your dock right click on it, edit, and then you can choose ether the icon and name for it.
Same thing with foldes, just instead choosing add file you choose folder... hope it can help you, if not you can find all the info you need here
http://www.aqua-soft...ead.php?t=50975